Tank Curing Came from Ireland
By: Eben van Tonder
11 March 2019
I have been researching the history of bacon curing now for many years. Evidence led me to conclude that tank curing originated in Denmark, I suspected, at the end of the 1900s. It was called “the Danish Method” and I know for a fact that the Harris operations from Wiltshire got the technology from Denmark. Many years ago I came across one old reference that certain bacon technology was taken from Ireland to Denmark in the mid-1800s. The reference was so vague that I did not once include it in any of my many articles. Despite much time spent on following it up I found no corroborating information. There was no reference of what the nature of the inventions could have been that was taken to Denmark,
In researching tank curing in Australia for my article, The Mother Brine, I suddenly had, not only the clearest and most complete description of tank curing but also a detailed account of its history. What is more, I had the name of the inventor, Mr. William Oake of Ulster. All this information came to me, courtesy of The Journal of Agriculture and Industry of South Australia, edited by Molineux, General Secretary of Agriculture, South Australia, Volume 1 covering August 1897 – July 1898 and printed in Adelaide by C. E. Bristow, Government Printer in 1898. By the time of writing in 1897 and 1898, Mr Oake has already passed away. According to the reference, he was a prolific chemist. The reason why I found no information is because I was looking for tank curing and the Irish called it “Mild Cure.”
Meeting Mr. William Oake of Limerick
It was 4:00, Monday morning, 11 March 2019 when I found the Australian reference and if I had any hope to get more sleep, it was gone! I was looking for corroborating circumstantial evidence that may verify this information. I started searching through old newspapers and immediately brought up fascinating results. There is a reference The Freeman’s Journal (Dublin, Dublin, Ireland), 23 September 1853 reporting that the previous Wednesday, letters from London “announced the disposal of the provisions contract for the royal navy, 12 000 tierces (casks) of pork and 4000 tierces (casks) of beef.” The short notice says that “we have the satisfaction to add that half the pork contract was taken for Irish account, and a considerable portion will be made up in Limerick, by Shaw and Duffield, William G. Gubbins, William Oake, and Joseph Matterson.” The article is quoting the Limerick Chronicle.
The information from Australia is clear that William Oake who invented tank curing is from Ulster and Limerick is in Munster, but I was unfased – we are definitely on the right island.
A notice was posted in Manchester Weekly Times and Examiner (Manchester), Saturday, 28 September 1889 of the death of William Horwood Oake from Gillingham, Dorset “elder son of the late William Oake of Limerick“, aged 49. This means that WH Oake was born in 1849 and if we presume William Oake from Limerick had him when he was 20, William was probably born around 1829. I later revised this estimate, taking more information into account and it seems that he was born around 1807. I give the full argument later in this article.
In The Bristol Mercury and Daily Post, Western Countries, 18 July 1885, page 8, a notice appeared for the dissolution of a partnership between William Howard (Horwood??) Oake, John Woods, and William Waring trading as Oake, Woods, and Waring, at Gillingham, Dorset. If the address is not a clear link to the son of William Oake from Limerick in Ireland, the commodities they traded in is the final proof and a picture is emerging of an imminent “bacon” family. They were, according to the notice, bacon and provision merchants. The partnership was dissolved due to Waring retiring. What is fascinating is that if (and there is good reason to suspect this), that William Oak from Limerick is the inventor of tank curing, this would indicate that by 1885 the process has not been exported to England since his son is selling the bacon which is, probably being imported from Ireland.
The circumstantial evidence is strong. William Oake had a substantial bacon curing operation and was able to do it at prices so substantially below curers in Britain that they were able to secure a large part of a lucrative Navy contract. The cost compared to dry salt curing is one of the main benefits if tank curing is compared to dry salting. The driving force for these was then, as it is today, cost and quality, but mainly cost. The other one that goes hand in hand with cost, is speed. Tank curing or mild curing is much faster than dry salting.
Britain was the main market for Ireland’s bacon and it stands to reason that the Irish would have been very protective over their technology. It makes sense that he set his son up to trade their bacon in England and did apparently not export the technology to England.
Events in Denmark and Ireland
A very strong third set of circumstantial evidence would now come to us from Denmark indicating that the Irish invention was first of all exported to the one country in the world who had as a national priority, the need to be able to do bacon better and at better prices than any other nation on earth. This country was Denmark.
It is curious that one of the first countries to received this Irish technology was in many respects similar to Ireland and in many respects better prepared to capitalise on the invention then even the Irish themselves. A fascinating article appeared in the Chicago Tribune (Chicago, Illinois) of 3 October 1897 entitled Why Ireland is in Want. The Recess Committee, established by the British Parliament to consider the creation of a department of agriculture and industry for Ireland, set out to look at the Danish model of agriculture as a possible solution for turning the Irish industry around. A comparison was made between Ireland and Denmark’s economies based on the fact that both countries are dependant on exports to Great Brittain with more or less the same mix of agricultural products being pork, butter, and bacon.
It sets the development of the bacon market in Denmark as having taken place beginning in 1889. Before 1888, Danish farmers relied on selling their pigs live to Germany. Swine Fewer hit Denmark in the autumn of 1887 which halted the export of live pigs. Exports to Germany fell from 230 000 in 1886 to only 16 000 in 1888. The creation of large bacon curing cooperatives was born out of the need to switch from exporting live pigs to processed pork in the form of bacon.
This was stunningly successful. In 1887 the Danish bacon industry accounted for 230 000 live pigs and in 1895, converted from bacon production, 1 250 000 pigs.
The Parliamentary Committee made another interesting observation that may shed light on a possible progression of events namely that due to the impoverished nature of the economy of Ireland, many people were forced to emigrate to seek a better life elsewhere. The people who emigrated were described by the committee as “the more energetic elements of the population” emigrated, taking with them skills that in the past was responsible for making Ireland a formidable rival of Great Brittain in commerce and manufacturing. The committee examined the causes for the change of fortunes of the individual Irishmen and the lack of competitiveness of its economy. It sought to juxtapose this with the much smaller and imminently more successful Danish economy.
The state of its bacon industry is of particular interest. The committee compared it to the Irish butter industry where the newest technology was introduced, but despite this, never achieved the competitiveness expected due to structural shortcomings in the system of agriculture. Bacon, it reported, was in a similar situation. The reason for the decline in bacon exports was due to the ability of the cooperatives of the Danish farmers (the chief competitor to Irish bacon) to produce better breeds of pigs, “a more rational system of feeding while the quality of the Irish pig has remained stationary.”
Another reason for the poor showing of Irish Agriculture, related to the pork trade, was the large trade between Ireland and Great Brittain in live animals. Switching to dead meat would be far more profitable for Ireland due to the inherent inefficiencies in selling live animals. The Danes were forced to move from live animals to selling dead meat due to the swine flue, but Ireland had no such restrictions and the logic of the benefits of dead meat to live animals, as was clearly seen by all, was not enough to get the farmers and traders to make the change. This in itself is an enormous lesson!
Does this fit the Timeline?
The switch of the Danish pork industry from selling live animals to producing and trading bacon happened from 1887, which would have been the perfect impetus for getting the new tank curing method from Ireland. It fits the timeline very well for the development of tank curing by William Oakes which would have been before 1853 when he and his partners secured the large contract for bacon from the British navy. But are these dates the right ones?
My suspicion was that they got the technology from Limerick simply because William Oake settled there.
Denmark getting hold of the Technology
In the end, the Danes did not get the curing technology from Limerick, but from Waterford in Ireland. The account comes to us, courtesy of Mr. T. P. Gill who was quoted in a letter that appeared to the editors by Peter Ryan in the Freeman’s Journal (Dublin, Dublin, Ireland), 8 October 1895, page 7 regarding cooperative agriculture.
Mr. Gill gave a lecture at the first general conference of the Cooperative and Agricultural Societies held at the Leinster Lecture Hall on the 25th, presumably of September 1895, on how the first cooperative bacon curing company was started in Denmark in 1887. Seven years earlier, in 1880, the Danes visited Waterford and “taking advantage of a strike among the pork butchers of that city, used the opportunity to bring those experts to their own country to teach and give practical and technical lessons in the curing of bacon, and from that date begins the commencement of the downfall of the Irish bacon industry. . . ”
The Irish probably “exported” mild curing technology to Australia even before it was taught in Denmark in 1880, yet no other country capitalised on the technology as did the Danes. Their system of cooperative farming, slaughtering and bacon curing allowed them to standardise not only the curing technology but also the pig breed best suited for bacon curing.
In what city was it invented?
This is a fascinating question. The Danes got the technology from Waterford, but is this where it was invented? The Journal of Agriculture and Industry of South Australia says that invention was done in Ulster, Northern Ireland. There is another account of the invention of Irish Mild Cured bacon I stumbled upon from a 1913 reprint of much older work from the Times. It says that Irish mild-cure was discovered by accident when a curer in Limerick, hard pressed for money, took his imperfectly cured bacon to the market before curing was completed. The short-cured bacon was apparently an instantaneous success and the method was soon developed. (Ireland of Today).
Of course, this account may be true, but I have serious doubts. I give the full mild cure method below as note 1. The account of not being able to complete the normal hard curing method does not fits any of the technical aspects of mild curing except being completed in a shorter time. I do not even think it influenced the actual invention.
I did a survey of the uses of the phrase “mild cure” on the online platform newspapers.com where all of the major newspapers from Britain and Ireland linked to the platform dating back several hundred years. There are many references from Limerick and Waterford from the 1840s and 1850s onwards. The very first reference, however, goes back to 1837 to a report from Antrim, Northern Ireland. It is fascinating that following this initial reference, Antrim completely disappears from the map and Limerick and Waterford takes over. This report simply said about bacon arriving from Ireland and that the Bacon market was dull the past week but for “a small parcel of mild cure.” (Belfast News-Letter (Belfast, Antrim, Northern Ireland) 21 July 1837)
Before this date – nothing. No mention al all! Remember that bacon was a commodity with prices regularly quoted in newspapers like maize today in South Africa in certain publications.
It is interesting that from this first reference, we have a steady increase in it’s prices being reported in newspapers.
The second reference is in 1842. Reporting in the Provisions section of Jackson’s Oxford Journal which would regularly report on bacon prices from Ireland. In a mention about produce from Ireland, it reports, “in the bacon market there is no great alterations; heavy bacon is more inquired after, and all fresh mild cure meets a fair demand.” Heavy bacon seems to be used as opposed to mild cure. (Jackson’s Oxford Journal (Oxford, Oxfordshire, England) 17 September 1842, p4)
The progression in the references, all related to bacon from Ireland and all focussed on amongst other, Limerick and Waterford. A 1945 reports said that “choice mild-cured Bacon continues brisk.” (Jackson’s Oxford Journal (Oxford, Oxfordshire, England) 26 July 1845, p4.)
A 1853 report from Ireland itself is very instructive. From Dublin, a report that says “We are glad to observe that several Dublin curers are now introducing the system of mild cure in bacon as well as hams, in consequence of the great difference had in price. (The Freeman’s Journal, (Dublin, Dublin, Ireland) 11 Feb 1853, p1)
From The Journal of Agriculture and Industry of South Australia, the following can be observed related to tank curing. He mentions that older brine is better and that that old brine has been used in one bacon factory which is 16 years old. This means that tank curing must have been in use in Australia at least by 1880. The reason is simple in that it will contain more nitrites.
He confirms the process of boiling the old brine and straining them once they get too muddy. Bacon curing was being thought through in terms of industrializing the process for high factory throughput. The person who wrote the article on Mild Cured Bacon in Australia makes the point that a very good way to overcome the barrier to entry of high equipment and factory cost is the cooperative system. In this comment, it seems that by 1897/ 1898 the cooperative model was widely marketed around the world and tank curing found an ideal corporate form in the cooperative model.
The use of the term mild cure is interesting. It is clear that it came to be used as a technical term describing tank curing. The term “milder cure” could have started as a description of the addition of sugar for the purpose of achieving a “less harsh cure”, i.e. a milder cure, but by 1830s it is clearly infused with a very particular technical reference to tank curing. The author of the Australian reference mentions that this kind of bacon is being preferred in all the large cities in Europe which possibly indicated the extent by which tank cured bacon of Denmark, Ireland and by this time, of England (through operations such as the Harris bacon plants) were being exported to other cities and, I am sure, that tank curing was being practiced in all these cities and replacing dry salt curing around the globe. A comment must be made about the Harris operation at this point, that they continued to take the best of every available system and merged it into what remained a complete system with its own unique character.
I quote the entire section on mild cure from the Australian publication in Note 1 below.
Does the age of Oake and his son fit what we know?
As promised, we return to the question of the likely age of Oake when he invented the cure and if it firs what else we know. We know that the invention must have taken place very close to the shipment of a small parcel of mild cured bacon to England from Ireland. Let’s assume that it happened 5 years before that date, in 1832. Let’s also assume that William, if he was the inventor, was 25 when he completed his studies and invented the system. That means he must have been born around 1807. We have the fixed date of the death of WH Oake. To make both sides work, this would mean that William was 33 in 1840 when his first son was born. It seems a bit late, but if his first three or four children were daughters, it works well. Here is my suggested timeline for William Oake: Born: around 1807; Invented mild cure: around 1832 (aged 25); WH born in (known date) 1840 (William, aged 33); 1889 WH passes (aged 49; known date and age; William, his dad would have been 82 if he was still alive). By 1897/1898 when the account is given in Australia, we know that William Oake was deceased. If he was still alive, he would have been 90.
The dates we know fits very well this likely recreation of the life of William Oake.
Evidence points to William Oake from Ireland as the inventor of the mild curing system or tank curing sometime before 1837. He was probably from Northern Ireland and trained as a chemist. That he set up a very successful bacon curing operation based on this system in Limerick, Ireland. The British firms, using dry salt curing were unable to compete with the lower cost of the new system. The UK was their largest client and his son, WH Oake, had a business selling his dad’s bacon in England for some years prior to 1885 in Gillingham, Dorset. The British Navy bought much of their bacon from Oakes bacon in Limerick.
The Danes imported the system into Denmark already in 1880 and when a large national drive transformed their pork industry from selling live animals to producing and exporting bacon in 1887, mainly to the UK, they were already well versed in the new technology. It is quite possible that the Harris Bacon Company changed to the same system during this time. The British Journal of Commerce reported in January 1889 that Calne was ‘the chief seat of the bacon-curing industry of England’. Harris bacon was being exported to many parts of the world including most European countries, America, Australia, India, China, the Cape of Good Hope, and New Zealand. There seems to be little doubt that they learned the technique, not from the Irish, but from the Danes.
Ten years later, by 1897/1898, mild cured or tank cured bacon was available at all major cities in Europe and Australia. It was probably taken to Australia by immigrants from Limerick. During the gold rush in the 1850s and 1860s, many Irish immigrants came to Victoria from amongst others, Limerick. It would not surprise me if such an immigrant was the source for Molineux or whoever wrote the section on Mild Curing in the Journal of Agriculture and Industry of South Australia. The descriptions are too vivid and crisp not to be from someone with intimate knowledge of the origin of the system. It may have been that the account came from someone who saw the system in Northern Ireland. I wonder why Limerick is not used instead of the reference to the northern Irish province?
My work is cut out for me as I have to dig deeper into the mystery and follow the various rabbit trains. I have already contacted several researchers and journalists in Limerick to assist me in my quest to learn more about William Oake.
I quote the entire section from The Journal of Agriculture and Industry of South Australia. A better treatment of tank curing of that time is as far as I know, not in existence. I can only imagine the Irish immigrants who brought this technology to Australia. After quoting it, I will make a few comments on the system.
“Bacon-Curing under the Factory System.
Like the dairying industry in latter years, the manufacture of bacon and hams has undergone great changes. The old expensive system of dry-salting has been almost entirely superseded by the less expensive method of curing with pickle in tanks. This method is not only less expensive, but it is the safest and most profitable for the climate of the Australian colonies.
There is at the present time a new process coming into vogue, which is attracting considerable attention amongst bacon-curers. The process is called the “mild cure.” The discoverer of the new process of curing was, it appears, an eminent chemist — the late Mr. William Oake. of Ulster. In an experiment, it is said he discovered that the antiseptic properties of salt were to be found apart from chloride of sodium (salt), and that the obnoxious effects of dissolving the albumen in the curing process could, therefore, be avoided. This is supposed to be the key to the new system of curing. By the new process of treatment, it is said that the bacon and hams, although thoroughly cured with the very essence of salt, still retain all the albumen originally in the meat, and yet do not taste salty to the palate. By the new process, the lean of the cured bacon remains soft and juicy, and natural in color; and the best proof of the value of the system is in the fact that where the mild cure has been adopted the bacon and hams will keep for any length of time in any climate. A great deal of labor, it is said, is saved by the new process, while the article put on the market is declared to be much superior in taste and flavor and quality to bacon cured on the old system.
Whatever may become of the new process, whether a success or not, it is certain that the time has now gone past for farmers to kill and cure for sale their own pigs to best advantage. The trade now requires an article well got up and of uniform quality to bring the highest prices, and as a rule, farmers have not the convenience for such work, and therefore are unable to compete against factories where they have all the latest appliances. It is therefore advisable for farmers either to co-operate and build a factory or to sell their pigs to some individual or company in the trade.
A factory with a capacity for working from 120 to 150 pigs per week, with refrigerating room and all machinery required, can be erected for about £1,000, and pigs of an average weight of 125lbs. can be killed, cured, smoked, and made ready for placing on the market at a cost of 4s. per head. In these times of keen competition and low prices, to make bacon-curing a profitable industry- no bacon should be held longer than from six weeks to two months, and hams from three to four months — the longer it is held the more weight it loses, and very often does not improve in quality.
The following is the system adopted in curing bacon with pickle. It is necessary to have a number of tanks, either built of brick and cement, slate, or wood. If timber is the most easily got, 2 1/2 in. planks well put together will answer. These tanks, if made 5ft. square by 40in. deep, will hold fifty ordinary sized pigs. Tanks sufficient for one week’s killing, with one spare tank for turning over the bacon, will be required.
Pigs that are to be killed should be kept without food for twelve or fourteen hours, and during that time should be yarded up adjoining the slaughter house. In no case should pigs be driven or heated in any way just prior to killing. From the yards to the killing pen a small race can be made, where from six to eight at a time can be run in and killed ; and the best method of killing is to stun the pig by a smart blow on the forehead, halfway between the eyes and the top of the head, with a hammer or similar weapon ; then, before the pig can struggle, turn him square on his back, place a foot on each side of the head, facing the animal, holding the head down to the floor by placing the left hand on the snout. Now place the point of the knife on the animal’s throat, at the same time looking over the carcass and pushing the knife in a straight line in the direction of the root of the tail. If you do not stick just right the first time, you will see why when the pig is opened. A little observation will enable you to become an expert pig sticker.
The killing pen should be raised from the ground about 2ft. 6in., and the floor allowed about 2in. fall. The blood will then flow all into one corner, where a receptacle can be placed underneath, and the blood all saved and used or sold for manure. From the floor of the killing pen the pigs can be drawn easily into the scalding vat, which should be placed adjoining the killing pen. A good size for the scalding vat is 6ft. long, 4ft. wide, and 2ft. 6in. high, and if a steam pipe is laid on from the boiler into the scalding vat the water can always be kept at a regular temperature — the best heat for scalding is 160°. Adjoining the scalding vat should be placed another vat of similar dimensions for cold water. After the pig is scraped it should be dropped into the vat of cold water, which will cleanse and cool the carcass and get the final scrape before being drawn up by the gamble on to the aerial tram, where the internals are removed and the backbone cut out, and then run into the factory, where they are allowed to hang till the following morning, when they are cut up into flitches or full sides, according to the size of the pigs.
As the carcasses are cut up the portions are laid on the floor of the factory (which should be made of concrete or flagged), flesh uppermost, and lightly powdered over with saltpetre, so as to drain off any blood. It can then be placed in the tanks for salting in the following manner: — Sprinkle the bottom of the tank with salt, then put in a layer of sides or flitches, sprinkle saltpetre over them lightly, and then salt and sugar. The next layer of sides or flitches is put in crosswise, and served in the same way, and so on until the tank is full. Then place a lid to fit inside the tank (inch battens 3in. apart will do) ; fix an upright on top of the lid to keep the bacon from rising when putting in the pickle. The pickle to be made as follows : — To every 1Olbs. of salt add 8lbs. of dark-brown sugar, lib. of spice, and 1/2lb. of sal-prunella. Make it strong enough to float an egg ; let it settle for some time, then skim, and it is ready to go on to the meat.
Explanatory note by Eben: Note Sal-Prunella is, according to Errors of Speech or Spelling by E. Cobham Brewer, Vol II, published by William Tegg and Co, London, 1877, a mixture of refined nitre and soda. Nitre, as used at this time was refined saltpeter used in the manufacturing of explosives.
At the end of forty-eight hours turn the meat over into another tank, taking care to put the sides that were on top in the bottom of next tank, treating it as regards saltpetre, salt, and sugar exactly the same as at first, and using the same pickle. It can then remain until the seventh day from when first put in. It can then be taken out, and stacked on the floor of the factory, putting some salt between each layer, but do not stack higher than four sides deep, until it has been on the floor for some days, when it should be turned over, and stacked higher each time until the fourth week from the day it went into the tanks; the bacon will then be cured.
The bacon can then be placed in tanks containing cold water, and allowed to soak all night. Wash well with a brush, then hang up to dry, and when properly dry it can be trimmed and smoked.
As hams require slightly different treatment from the bacon, separate tanks are required. Before placing the hams in the tank rub over the face of each one a thin layer of brown sugar. When the first layer is placed in the tank sprinkle over with saltpetre and salt, same as with the bacon, treating the balance the same as at first until the tank is full. Make the pickle same as for bacon, and leave the hams same time in tanks. Always retain the same pickle for the hams, and in no case use the bacon pickle for hams. The same pickle can be used for many years — the older the better; it only requires, when it becomes somewhat muddy, to be boiled and clarified. I have seen pickle which had been used in one factory for sixteen years, and that factory produces some of the best bacon and hams in Australia.
Explanatory note by Eben: This means that tank curing or “mild cure” as it was called, was in use in Australia at least by 1880.
Smoking Bacon and Hams.
The smokehouse should be built according to the intended output of bacon and hams, and the walls of the building should not be less than 12ft. high. One of the principal things in smoking bacon is to have the smoke as cool as possible before coming into contact with the bacon, and to assist this it is well to put a floor 6ft. 6in. or 7ft. from the ground, just allowing a slight opening between the flooring boards to allow the smoke to make its way up to where the bacon is hung. The flitches or hams should be hung as close together as not to touch, so as to allow the smoke to penetrate every portion. A small slide can be put in the gable of the smokehouse to regulate the smoke as required. A place should be made in the centre of the floor, say 6ft. by 3ft., where the sawdust is placed. This is lighted, and if the door is kept closed there will be no flame, but the sawdust will smoulder and cause a great quantity of smoke. From twenty-four to forty-eight hours will suffice to properly smoke the bacon if the weather is suitable, after which it may be packed and forwarded to market.
Where teatree (Melaleuca) is obtainable it is excellent for smoking ; it imparts a flavor to the bacon which is much appreciated by many people.
A Conclusion is offered
Mild-cure Bacon. — In all of the large cities of Britain and the European continent, the public demand is for mild-cure bacon. The system of cure is very simple and perfect, but requires expenditure of at least £1,000 on the plant for carrying it out. By this process the albumen of the meat is retained and is not coagulated, so that the bacon is devoid of excessive salt, is by no means hard or dry, and there is no loss of weight in the curing. A factory costing £2,000 to construct could easily cure 400 pigs per day. The process takes about a month to complete, but after the first day there is no further labor involved.”
All references are properly given in the text except,
Ireland of Today. Reprint with some additions. 1913. The Times. John Murray Albemarle Street, W..
This historical review spans many millennia. From the dawn of humanity as we know it to our current time where we touch on modern developments in meat curing technology. It started out as a way of managing food scarcity by providing a means of fortifying meat against spoilage and over time became a culinary craft. Here I review some of the developments in brine technology as well as the technology of administering the brine to the meat and accomplish curing in the shortest possible time. This review is done from the perspective of a commercial mainstream high throughput bacon plant and not from the viewpoint of artisan curing operations, some of which are large and service a large client base. It is a work in progress as my own understanding evolves of this great art, the art of curing. This historical review of the curing process yields interesting perspectives.
Curing is a fascinating process. A modern understanding of the benefits of curing is that it fixes a pinkish-reddish cured meat colour. It endows the meat with unique longevity, even if left outside a refrigerator, many times longer than that of fresh meat. It is powerful enough to prevent the deadly toxin formation by Clostridium botulinum. It prevents rancidity of fat. It lastly gives meat a unique cured taste.
Discovering the mechanics behind meat curing was a slow process that took hundreds of years. (For an overview of some of the people behind the most important discoveries, see Fathers of Meat Curing) A survey of farm curing methods conducted in 1951 by the US Department of Agriculture among farmers in the US revealed the following brining methods used:
Salt Only (Dry cure – no pumping – salt only – using dry salt or brine)
Exactly where salt curing of meat started is an interesting question. There is ample evidence that salt preservation of meat was done from the earliest of times.
Despite that fact that there are records of fish being salt cured in China going back to 2000 BCE and from Egypt and Mesopotamia, the practice is much older.
For years I believed that a piece of dry-cured meat was discovered dating back to 5300 years ago (3300 BCE). In September 1991, two German hikers from Nuremberg, Helmut and Erika Simon, stumble across the naturally mummified remains of a Copper Age man while wandering through an Alpine glacier at the border between Austria and Italy, on the Austrian-Italian region, in the Ötztal Alps. What they thought was a hiker who perished recently turned out to be the oldest mummified frozen mummy known today. He is estimated to have lived in 3,300 BCE and more specifically between 3359 and 3105 BCE. It is calculated that there is a 66 percent chance that he died between 3239 and 3105 BCE.
It was widely reported that his last meat was cured meat. I quote from the article where this was reported. “Researchers thawed his body and have been able to test the contents of his stomach. Mummy specialist Albert Zink from the European Academy of Bolzano said he was able to analyse the nanostructure of meat fibers from a mountain goat found in Ötzi’s stomach – indicating that the meat was raw and had been dry-cured, and not cooked or grilled, which would have weakened the fibers. He added that Ötzi did not have a proper hunting bow with him, and probably carried the dried meat with him from his home, as raw meat would have quickly gone bad. Further analysis of his stomach contents showed that he had not eaten cheese or dairy products, just meat. “It seems probable that his last meal was very fatty, dried meat – perhaps a type of Stone Age speck or bacon,” Zink said. As Ötzi had hiked down from the South Tyrolean side of the Alps, it’s likely his provisions came from there.” (The Local)
I liked Ötzi-man even more since there is good evidence linking him with China, also established by the content of his stomach. When researches tested the contents of his stomach, “they found a bacterium called Helicobacter pylori, an age-old pathogen that has evolved into different strains according to the region of the world in which it is found. About half the people on the planet harbour the bacterium in their stomachs. It can cause ulcers or gastrointestinal distress and is typically spread among children when they play in the dirt. While researchers cannot be sure if the Iceman was sick due to the infection, they were intrigued by their analysis of the geographic history of the bacterium. “Surprisingly, a strain of bacterium in his gut shares ancestry with an Asian strain,” said the study in the US journal Science. “In contrast to the fact that most modern Europeans harbour a strain ancestral to North African strains.”” (The Local/AFP) This was interesting to me since this would be a link relating dry curing with salt and China.
I have, however, serious doubts if this actually tells us anything about dry curing of meat and if his Asian wonderings shed any light on the link between dry curing and China. Ancients consumed their food raw before it was discovered how to make fire. (How did Ancient Humans Preserve Food?) Even after fire making was invented and the technology became universally part of human culture, humans only cooked their food intermittently for a very long time. There are cultures to this day who eat raw meat in one form or the other. Besides this, hanging meat to dry in the sun, the wind or over a fireplace without adding any curing agent like salt was practiced in Southern Africa, North America, and Nepal, to mention just a few places that I am personally aware of. It was likely universally practiced at some point in the past. We simply do not know exactly how Ötzi-man preserved his meat.
After a careful investigation of the use of salt for meat preservation in Southern Africa, the evidence points to the fact that the power of salt to preserve meat was known by for example the Khoe and the San people, but they preferred to simply hang meat in the sun and the wind to dry if this was ever necessary. (Salt and the Ancient People of Southern Africa)
What we know for sure is that salt curing of meat occurred in China from very early on. Flad, et al. (2005) showed that salt production was taking place in China on an industrial scale as early as the first millennium BCE at Zhongba. “Zhongba is located in the Zhong Xian County, Chongqing Municipality, approximately 200 km down-river along the Yangzi from Chongqing City in central China. Researchers concluded that “the homogeneity of the ceramic assemblage” found at this site “suggests that salt production may already have been significant in this area throughout the second millennium B.C..” Significantly, “the Zhongba data represent the oldest confirmed example of pottery-based salt production yet found in China.” (Flad, et al.; 2005)
Salt-cured Chinese hams have been in production since the Tang Dynasty (618-907AD). First records appeared in the book Supplement toChinese Materia Medica by Tang Dynasty doctor Chen Zangqi, who claimed ham from Jinhua was the best. Pork legs were commonly salted by soldiers in Jinhua to take on long journeys during wartime, and it was imperial scholar Zong Ze who introduced it to Song Dynasty Emperor Gaozong. Gaozong was so enamored with the ham’s intense flavour and red colour he named it huo tui, or ‘fire leg’. (SBS) An earlier record of ham than Jinhua-ham is Anfu ham from the Qin dynasty (221 to 206 BCE).
In the middle ages, Marco Polo is said to have encountered salt curing of hams in China on his presumed 13th-century trip. Impressed with the culture and customs he saw on his travels, he claims that he returned to Venice with Chinese porcelain, paper money, spices, and silks to introduce to his home country. He claims that it was from his time in Jinhua, a city in eastern Zheijiang province, where he found salt-cured ham. Whether one can accept these claims from Marco Polo is, however, a different question.
The reach of Chinese technology of salt production was nevertheless impressive. I recently visited New Zealand where I learned that the Māori never developed salt extraction in any form. I did a short review of the colonization of Indonesia and salt extraction technology in an article, “Concerning the lack of salt industry in pre-European New Zealand and other tales from Polynesia and the region” A brief survey of the history of salt extraction from Fiji, Samoa, New Guinea, Vanuatu, and Taiwan shows the large influence of China on regional salt production technology.
This study also revealed a possible forerunner of more formal salt production around the world, including China. One of the earliest ways that salt found itself in food preparations was undoubtedly through the fact that seafood was consumed that naturally had added salt which came from the water. Immersing carcasses of animals and fish in water would have been one of the earliest forms of preservation and since earliest communities gravitated to coastal regions, salt water would have been often used and in addition to seafood which is rich in salt, it would have entered early human culture in this way. It is likely that carcasses were stored in water at first to hide them from predators and its preserving power would soon have been discovered. Migrating groups would have noticed how seawater preserved meat better and changed (improved) the taste of the meat.
The study of salt in Polynesia shows that as groups migrated inland, away from the sea, saltwater was boiled to evaporate the water and leave the salt as a very basic salt extraction technique. The salt was then traded with the inland communities. This was widely practiced in Taiwan until fairly recently. The references of it in Polynesia and Asia offers a suggested progression of the extraction of salt from seawater. Studies from Fiji identified population size, even of coastal communities to be a key driver development of salt extraction technology. Inland communities had the added problem by its removal from seawater.
It would be my guess that migrants from Taiwan spread their technology throughout the lands of Polynesia. Every evaluation of salt on the islands I looked at supports this. China would undoubtedly have been a key driver in the region in progressing salt extraction technology with Pappa New Guinea playing a large role where a multitude of techniques to extract salt was (and still is) in use. Solar evaporation of seawater, extracting salt through plant material and burning plants, naturally high in salt are a few of the developments from the region, which all presumably have their roots in the practice of simply boiling seawater; in turn, this was probably a progression of the practice of cooking food in seawater; which, in turn had its roots in storing meat in saline solutions; which had its roots in simply immersing carcasses in bodies of water for storage. When we are at this point, we are clearly at the very early age of the existence of cognitive modern humans who were cognitively similar to modern humans.
In a discussion with a curator from the Canterbury Museum about the matter of salt production and trade in salt being absent from New Zealand ancient history, he drew my attention to the interesting practice of the Maori to slow boil large quantities of shellfish. Had they not done so, it would not have been possible to consume large quantities at a time. There seems to be evidence that they did, in fact, consume large quantities of this at a time. It supports the notion that they knew about salt and the possibility exists that this was true across the world from very early. People probably knew at least some of the techniques for extracting it, but some local populations, as was the case in New Zealand, may never have used the technology simply because it was not necessary. In the case of the Maori’s, they definitely knew to remove some of the salt from shellfish before consuming it. (They have a word for salt which shows that they definitely knew about its taste).
Salt as a condiment
One can not talk about salt curing and not at least make mention of its use as a condiment. Even though too much salt alters the taste negatively, preservation through salt and altering (enhancing) the taste go hand in hand. Evidence is emerging about the use of condiments in food, the earliest discovery to date in Europe going back 6000 years ago in Germany and Denmark. ARCHEOLOGY magazine Nov/ Dec 2013 reports that “a team of researchers has found phytoliths, small bits of silica that form in the tissues of some plants, from garlic mustard seeds, which carry strong, peppery flavor but little nutritional value. Because they were found alongside residues of meat and fish, the seed remnants represent the earliest known direct evidence of spicing in European cuisine. According to researcher Hayley Saul of the University of York, “It certainly contributes important information about the prehistoric roots of this practice, which eventually culminated in globally significant processes and events.”” (Archeology) Salt would undoubtedly have been part of their arsenal of taste enhancers.
It seems that our relationship with salt has never been static and to this day, it continues to evolve. More importantly, the discoveries in Denmark and Germany brings into focus innovations in the European lands of Germany, Austria, Hungary, the Czech Republic, Switzerland, Denmark, Holland, Belgium, Spain, France, and Poland. Besides these, there is Irland. What was happening in these regions while cities and kingdoms covering Mesopotamia, India, Pakistan, Nepal were developing salt industries and very sophisticated meat curing technologies based on salt, nitrate, and sal ammoniac? I am filling in the gaps over the years to come.
Origins of Nitrate/ Nitrite curing?
This study of salt also brings me back to my work on nitrite/ nitrate curing which has been a major focus for me over many years. While people living in desert areas would have discovered that certain salts have the ability to change the colour of meat from brown, back to pinkish/ reddish, along with increased preservation power and a slightly distinct taste, it is certainly true that coastal dwellers would have observed the same. They would have noticed that seasalt or bay salt have the same ability.
Dr. Francois Mellett, a renown South African food scientist, sent me the following very interesting theory about the earliest discovery of the curing process in private communication between us on the matter. He wrote, “I have a theory that curing started even earlier by early seafarers: when a protein is placed in seawater, the surface amino acids are de-aminated to form nitrite for a period of 4 to 6 weeks. Nitrite is then converted to nitrate over the next 4 weeks. Finally, ammonia and ammoniac are formed from nitrate. It is possible that they preserved meat in seawater barrels and that the whole process of curing was discovered accidentally.”
I think he is on the right track. I suspect that people discovered this even long before barrels were invented. The use of seawater for meat storage and further preparation was so widespread that it would have been impossible not to have noticed meat curing taking place. If it is generally true that earliest humans first settled around coastal locations before migrating inland, it could push the discovery of curing many thousands of years earlier than we ever imagined, to a time when modern humans started spreading around the globe. When did it develop into an art or a trade is another question altogether, but I think we can safely push the time when it was noticed back to the earliest cognitive and cultured humans whom we would have recognized as thinking “like us” if we could travel back in time and meet them. I think the question of recognition in different regions we can safely put at the time when these areas were populated.
We know that dry-curing of pork takes around 5 to 6 weeks under the right conditions and if the meat is not cut too thick. It must be cool enough that the meat doesn’t spoil before it is cured. Even though I now suspect that curing was first noticed by communities living by the sea as I just explained, I suspect that curing salts in deserts were discovered since natural salts always appear as a mix of various salts and under certain conditions, these salt deposits contain small amounts of nitrate salts and ammonium chloride.
The ancients would have noticed this. I deal with these salts below under separate headings, but the most important two curing salts that appear to us from antiquity are saltpeter (sodium nitrate) and sal ammoniac (ammonium chloride). Both salts were well known in Mesopotamia and references to them appear alongside references to salt curing of fish mentioned earlier and both salts were used in meat curing.
The ancients developed basic techniques of separating out the different salts. In particular, sal ammoniac was by far the more important salt of the bronze age (2000 BCE). It was produced in Egypt and mined in Asia. There are features of sal ammoniac that favours it as a salt for people who had a motivation to exploit new lands due to population pressure and climate changes. When the horse was domesticated around 5000 BCE, a food source was needed to sustain them on long expeditions and I believe sal ammoniac fits the requirement perfectly.
Both salts cure the meat in a week which obviously had huge advantages over salt-only curing. This, I speculate, was the first incentive to change to a dedicated curing salt. Secondly, sal ammoniac, as far as I can find, was globally traded from much earlier on than saltpeter. Ancient Macedonian records indicate that even 2000 BCE saltpeter was preferred in food over sal ammoniac on account of the better taste of saltpeter.
There is a modern era example of a curing technique that was good for a time and was then replaced with more agreeable methods as soon as supply lines were established. This technique, I believe actually existed from very early after the horse was domesticated and was re-introduced by various cultures, at various times. One such culture was the Boers who left the Cape Colony and moved into the interior of South Africa. The technique they used to cure their meat disappeared as soon as conventional supply lines were established.
The technique is curing of meat by hanging it over the neck of the horse or placing it under your saddle so that the sweat of the horse cure the meat. (For a discussion on this, see my article, Saltpeter, Horse Sweat and Biltong) My point is that this is a good example of a curing technique that was used for a time only and then disappeared, only to be re-appear when conditions required it. Such was the case, I suspect when sal ammoniac was used for a time in curing until the requirement subsided, salt curing became popular again and much later economic factors re-introduced saltpeter curing.
German and Austrian cookbooks pre-1600’s reveal that vegetable dyes were used to bolster colour in this time and speak of curing with salt only. It is well known that the Germans and Austrians were familiar with nitrate curing and, I will argue, they would have been acquainted with sal ammoniac as a curing salt also, but for whatever reason, these fell out of common practice. When the requirements disappeared for nitrate and sal ammoniac curing of the ancient world, the nations of Europe and China reverted to salt curing.
The many references to salt curing are therefore not surprising in the context of a mature and stable society. A record exists from Cato the Elder who described in 160 BCE. how a ham should be cured. In his Latin work, De Agricultura (On Farming), this Roman statesman and farmer, gives an ancient recipe for curing pork with salt.
“After buying legs of pork, cut off the `feet. One-half peck ground Roman salt per ham. Spread the salt in the base of a vat or jar, then place a ham with the skin facing downwards. Cover completely with salt. After standing in salt for five days, take all hams out with the salt. Put those that were above below, and so rearrange and replace. After a total of 12 days take out the hams, clean off the salt and hang in the fresh air for two days. On the third day take down, rub all over with oil, hang in smoke for two days…take down, rub all over with a mixture of oil and vinegar and hang in the meat store. Neither moths nor worms will attack it.” (economist.com)
Cato may have imitated a process whereby hams are smoked over juniper and beech wood. The process was probably imported by the Roman gourmets from Germania. (economist.com) It is possible that the process of curing itself was brought to Rome by the military stationed in Germany.
Salt curing remains an important technique for high-end hams and certain bacons. Like nitrite curing, it yields a particular cured colour, but one that is more deep purple than pink. For the mechanism behind this, refer to a section in my article on the mechanisms of nitrite curing, BACTERIAL/ ENZYMATIC CREATION OF CURED COLOUR.
In 2017 I did an article where I speculated that nitrate curing originated from either the Turpan area in western China or from the Atacama desert in Chile and Peru. In this article, I suggest that nitrate curing of meat is thousands of years old. (Salt – 7000 years of meat-curing) I was working on the assumption that nitrate salts are the only salts that will yield nitrite and nitric oxide, required for meat curing. Between the Atacama desert and Turpan in Western China, Turpan is by far the best candidate for the birthplace of meat curing as it is practiced around the world. I recently review further evidence from this area in an article, Nitrate Salts Epic Journey and And then the mummies spoke!
In the course of researching the article, I discovered that sal ammoniac was far more vigorously traded than saltpeter in the early Christian era and possibly for thousands of years before that. Fascinatingly enough, I realised that ammonium chloride will, like nitrates, undergo bacterial transformation into nitrites which will, then, in the meat matrix yield nitric oxide which will cure the meat. I further discovered that it is an excellent meat preservative. Turpan is also probably the only place on earth where sal ammoniac and nitrate salts in the form of sodium nitrate occur in massive quantities side by side.
Chinese authors of antiquity are unanimous that sal ammoniac came into China from Turpan, Tibet, and Samarkand and through Samarkand, it was traded into the Mediterranian along the silk road. There are similar records that it was traded from Turpan along the silk road through the city of Samarkand who had strong trading ties with the Mediterranean. It all makes for an appealing case for sal ammoniac as the actual curing salt from antiquity that was used in meat curing when the practice spread around the world. There is even a tantalizing link between Turfan and the ancient city of Salzburg and the salt mines which leads me to speculate that the trade of sal ammoniac was done into the heart of Western Europe, into what became known as Austria. This leads me to believe that the actual technological progressions may have come from Austria. Whether it was Salzburg or Turfan is not clear.
We are not familiar with this salt in the context of meat curing and more information is in order. I reviewed modern references dating back to the 1700s, 1800s, and 1900s where it continued to be used in meat preservation in Nitrate Salts Epic Journey. Several minerals exist composed of ammonium (NH4). Ammonium is formed by the protonation of ammonia (NH3). Sal ammoniac is the most well known and was named by the ancient Romans. They collected this salt which was found around the temple of Jupiter Ammon in Egypt and called it salt (sal) of Ammon (ammonocius). The name ammonia was subsequently derived from it. It forms in volcanic vents and after volcanic eruptions before it has rained which dissolves it. It is highly soluble. It is unique in that the crystals are formed directly from the gas fumes and bypass the liquid phase, a process known as sublimation.
Ammonium readily combines with an acid thus forming a salt such as hydrochloric acid to form ammonium chloride (sal-ammoniac) and with nitric acid to form ammonium nitrate. Recent studies have shown that volcanos release a “previously unconsidered flux of nitric acid vapour to the atmosphere. (Mather, T. A., et al, 2004) It is a fact is that the Turfan area, both the basin and the mountains are replete with different salts containing nitrogen (nitrate salts and ammonium) any one of which could be used effectively in meat curing.
The sal ammonia was mined from openings in the sides of volcanic mountains where steam from underground lava flows created the ammonium chloride crystals. These were traded across Asia, Europe and into India. Massive sodium nitrate deposits occur in the Tarim basin, the second lowest point on earth. I then speculate that traders used some of these deposits to forge ammonium chloride since the ammonium chloride crystals did not survive in crystal form on long voyages due to its affinity for water that breaks the crystal structure down. Once this happened, the sodium nitrate and the ammonium chloride look similar in appearance. Due to the fact that it is known that almost all the sal ammonia produced in Samarkand was exported, I deduce that demand outstripped supply and this provided the incentive for such forgery. I find support for the likelihood of such a forgery, not just in the limited supply of sal ammoniac compared to nitrate salts, but also in the fact that mining then sal ammoniac was a seasonal affair and extremely dangerous and a difficult undertaking.
It seems likely that sal ammonia wasthe forerunner of saltpeter as the curing agent of choice. It is composed of two ions, ammonium, and chloride. The ammonium would be oxidized by ammonia-oxidizing bacteria (AOB) into nitrites and the well-known reaction sequence would result. Reaction Sequence
Not only would it result in the reddish-pinkish cured colour, but it was an excellent preservative. An 1833 book on French cooking, The Cook and Housewife’s Manual by Christian Isobel Johnstone states that “crude sal ammonia is an article of which a little goes far in preserving meat, without making it salt.” (Johnstone, C. I.; 1833: 412) It is, of course, the sodium which tastes salty in sodium chloride and ammonium chloride will have an astringent, salty taste. I know exactly what ammonium chloride taste like since it was added to my favourite Dutch candy “Zoute Drop” with licorice. I believe it was none other than my old friend, Jan Bernardo who first gave me Zoute Drop. As a boy, I used to ride my bicycle once a month to the only Greek Caffe in Vanderbijlpark which sold it for my monthly fix. My favourite was the double strength version called “Dubbel Zoute Drop.”
Subsequent to these discoveries, I did two small tests with sal ammoniac. Refer to the Sal Ammoniac Project. Here I show that sal ammoniac stands up to its reputation as an excellent preservative and definitely cures meat in two weeks at a 5 deg C temperature.
Saltpeter is the curing salt that most of us are familiar with that preceded sodium nitrite as curing agent. By far the largest natural known natural deposits of saltpeter to the Western world of the 1600s were found in India and the East Indian Companies of England and Holland plaid pivotal roles in facilitating its acquisition and transport. The massive nitrate fields of the Atacama desert and those of the Tarim Bason were still largely unknown. In 1300, 1400 and 1500 saltpeter had, however, become the interest of all governments in India and there was a huge development in local saltpeter production.
In Europe, references to natron emerged from the middle of the 1500’s and were used by scholars who traveled to the East where they encountered both the substance and the terminology. Natron was originally the word which referred to saltpeter. Later, the word natron was changed and nitron was used.
At first, the saltpeter fields of Bihar were the focus of the Dutch East Indian Company (VOC) and the British East Indian Company (EIC). The VOC dominated the saltpeter trade at this point. In the 1750s, the English East Indian Company (EIC) was militarised. Events soon took place that allowed for the monopolization of the saltpeter trade. In 1757 the British took over Subah of Bengal; a VOC expeditionary force was defeated in 1759 at Bedara; and finally, the British defeated the Mughals at Buxar in 1764 which secured the EIC’s control over Bihar. The British seized Bengal and took possession of 70% of the worlds saltpeter production during the latter part of the 1700s. (Frey, J. W.; 2009: 508 – 509)
The application of nitrate in meat curing in Europe rose as it became more generally available. Later, massive deposits of sodium nitrite were discovered in the Atacama Desert of Chile and Peru and became known as Chilean Saltpeter. This was, as I have said before, only a re-introduction of technology which existed since 2000 BCE.
The pivotal area where I believe saltpeter technology spread from across Asia, India and into Europe, is the Turpan-Hami Basin in the Taklimakan Desert in China. Here, nitrate deposits are so substantial, that an estimated 2.5 billion tons exist, comparable in scale to the Atacama Desert super-scale nitrate deposit in Chile. (Qin, Y., et al; 2012) (THE TARIM MUMMIES OF CHINA) Its strategic location on the silk road, the evidence of advanced medical uses of nitrates from very early on and the ethnic link with Europe of people who lived here, all support this hypothesis.
Large saltpeter industries sprang to the South in India and to the South East in western China. In India, a large saltpeter industry developed in the north on the border with Nepal – in the state of Bihar, in particular, around the capital, Patna; in West Bengal and in Uttar Pradesh (Salkind, N. J. (edit), 2006: 519). Here, it was probably the monsoon rains which drench arid ground and as the soil dries during the dry season, capillary action pulls nitrate salts from deep underground to the surface where they are collected and refined. It is speculated that the source of the nitrates may be human and animal urine. Technology to refine saltpeter probably only arrived on Indian soil in the 1300s. Both the technology to process it and a robust trade in sal ammoniac in China, particularly in western China, predates the development of the Indian industry. It is therefore unlikely that India was the birthplace of curing. Saltpeter technology probably came from China, however, India, through the Dutch East Indian Company and later, the English East Indian Company became the major source of saltpeter in the west.
To the South East, in China, the largest production base of saltpeter was discovered dating back to a thousand years ago. Here, a network of caves was discovered in 2003 in the Laojun Mountains in Sichuan Province. Meat curing, interestingly enough, is also centered around the west and southern part of China. Probably a similar development to the Indian progression.
In China, in particular, a very strong tradition of meat curing developed after it was possibly first introduced to the Chinese well before 2000 BCE. Its use in meat curing only became popular in Europe gain between 1600 and 1750 and it became universally used in these regions towards the end of 1700. Its usage most certainly coincided with its availability and price. I have not compared price and availability in Europe with the findings on its use in meat curing which is based upon an examination of German and Austrian kook books by Lauder (1991), but I am confident that when I get to it one day, the facts will prove the same.
The Dutch and English arrived in India after 1600 with the first shipment of saltpeter from this region to Europe in 1618. Availability in Europe was, generally speaking, restricted to governments who, in this time, increasingly used it in warfare. (Frey, J. W.; 2009) This correlates well with the proposed time when it became generally available to the European population as the 1700s from Lauder. I believe that a strong case is emerging that the link between Western Europe and the desert regions of Western China was the place where nitrate curing developed into an art. The exact place, I believe, in Western China is the Tarim depression.
Dry curing of meat changed from salt only to a mixture of salt and saltpeter, liberally rubbed over the meat. As it migrates into the meat, water and blood are extracted and drained off. The meat is usually laid skin down and all exposed meat are plastered with a mixture of salt and saltpeter. Pork bellies would cure in approximately 14 days. (3) (Hui, Y. H., 2012: 540)
The addition of sugar which favours the reduction of nitrate to the active agent nitrite became common practice during the 19th century.” (Lauer K. 1991.) At first, it was added to reduce the saltiness of the meat and make it generally more palatable. Curers soon discovered that when sugar is added, the meat cures faster and the colour development is better.
Science later revealed that the sugars contribute to “maintaining acid and reducing conditions favourable” for the formation of nitric oxide.” (Kraybill, H. R.. 2009) “Under certain conditions reducing sugars are more effective than nonreducing sugars, but this difference is not due to the reducing sugar itself. The exact mechanism of the action of the sugars is not known. It may be dependent upon their utilisation by microorganisms or the enzymatic systems of the meat tissues.” (Kraybill, H. R.. 2009)
Ralph Hoagland, Senior Biochemist, Biochemie Division, Bureau of Animal Industry, United States Department of Agriculture, discovered that saltpeter functional value upon the colour of meat is its reduction to nitrites and the nitrites to nitric oxide, with the consequent production of NO-hemoglobin. He showed that the reactant is nitrous acid () or one of its metabolites such as nitric oxide ().
He wrote an important article in 1921, Substitutes for Sucrose in Cured Meats. Writing at this time, this formidable meat scientist is ideally placed to comment on the use of sugar in meat curing in the 1800s since the basis of its use would have been rooted in history.
He writes about the use of sugar in meat curing in the USA and says that it is used “extensively.” He reveals that according to government records, 15,924,009 pounds of sugar and 1,712,008 pounds of syrup, totaling 17,636,017 was used in curing meats in pickle in establishments that were inspected by the US Government, in 1917. If one would add the estimated use of sugar in dry cures in the same year, he placed the usage at an estimated total of 20,000,000 pounds. This estimate excludes the use of sugar in meat curing on farms. (Hoagland, R. 1921.)
Hoagland says that the functional value of sugar in meat curing at this time (and probably reaching back into the 1800’s) was entirely related to product quality and not preservation. “Sugar-cured” hams and bacon were viewed as being of superior quality. He states that a very large portion of bacon and hams produced in the USA are cured with sugar or syrup added to the cure. The quantity of sugar used in the curing mix is so small that it does not contribute to meat preservation at all. “Meat can be cured in entire safety without the use of sugar, and large quantities are so cured.” (Hoagland, R. 1921.)
The contribution to quality that he speaks about is probably related to both colour and flavour development. The colour development would have been related to the formation of the cured colour of the meat (The Naming of Prague Salt) as well as the browning during frying.
The role of sugar in bacon curing of the 1800’s when saltpeter was used was elucidated in 1882 by Gayon and Dupetit, studying and coining the term “denitrification” by bacteria. The process whereby nitrate in changed to nitrite is through the process of bacterial denitrification. They demonstrated the effect of heat and oxygen on this process and more importantly for our present discussion, “they also showed that individual organic compounds such as sugars, oils, and alcohols could supplant complex organic materials and serve as reductants for nitrate.” (Payne, 1986)
Denitrifying bacteria are facultative anaerobes, that is, they will only use nitrate () if oxygen () is unavailable as the terminal electron acceptor in respiration.” “The is sequentially reduced to more reduced forms although not all bacteria forms gas. ” “Many bacteria can only carry out the reduction of to , and this process is referred to as dissimilatory nitrate reduction. There is also evidence emerging that certain bacteria can denitrify, even if is present. (Seviour, R. J., et al.. 1999: 31)
(Seviour, R. J., et al.. 1999: 31)
“The rate of denitrification is affected by several parameters including temperature, dissolved oxygen levels and the concentration and biodegradability of carbon sources available to these cells” (Seviour, R. J., et al.. 1999: 223) Examples of such carbon sources are sugar, oxygen and plant oils.
In the 1800’s when the use of saltpeter was at its pinnacle, the use of sugar with saltpeter had then a much more prominent role in that it energizes denitrification bacteria which results in an increased rate of nitrate reduction to nitrite and therefore would speed up curing with saltpeter and result in a better overall curing process. Today, with the widespread use of sodium nitrite in curing brines, certain denitrifying bacteria is one mechanism for NO formation which directly leads to better curing.
The use of sugar or dextrose in bacon production in the modern era has more to do with the browning effect through by the well-known Millard reaction to give fried bacon a nice dark caramel colour when fried.
Dry-salt-curing in combination with injection (dry cure – with pumping)
It seems that the basic definition distinguishing between dry and wet curing is not based on whether injection is applied or not, but the state of the salts that the meat is left in, even after it has been injected with a brine (mixture of salt and water). So, if it is packed in a dry mix, it is dry curing and if it is soaked in a brine, it is wet-curing.
One of the prominent inventors of the technology to inject brine directly into meat to speed up the brine absorption was a certain Mr. Morgan, in England. The motivation was to increase the rate of curing in order to reduce the time required for processing. In temperatures above 20 deg C, pork spoils in three days.
It was important for farmers to cure the meat before a warm snap could allow spoilage organisms to work before the cure was properly diffused through the meat. Later, in industrial plants, the drive for a faster curing time would be cost factors. Increased output with limited and expensive equipment and people.
By injecting a liquid brine into the meat at evenly spaced intervals, the brine would diffuse quicker through the meat. It is also important to state that his interest was the preserving of meat generally for example for long sea voyages and not the curing of meat by farmers. The application of his method of injection, however, found its way into many homes and factories around the world.
Edward Smith writes in his book, Foods, in 1873 and accounts the events of “Mr. Morgan [who] devised an ingenious process by which the preserving material, composed of water, saltpeter, and salt, with or without flavouring matter, was distributed throughout the animal, and the tissue permeated and charged. His method was exemplified by him at a meeting of the Society of Arts, on April 13, 1854, when I [Edward] presided.” (Smith, E, 1873: 35)
He describes how an animal is killed in the usual way, the chest opened and a metal pipe connected to the arterial system. Brine was pumped through gravity feed throughout the animal. Approximately 6 gallons were flushed through the system. Pressure was created to ensure that it was flushed into the small capillaries. Smith reported overall good results from the process with a few exceptions. He himself seemed unconvinced.
An article appeared in the Sydney Morning Herald that mentions Dr. Morgan and his arterial injection method. An important observation from the article is the date of 1870. By this date, he is referred to as “Dr. Morgan”, cluing us in about the timeline of Morgan’s life.
A second observation is a drawback of the system. The article states that “salting is the most common and best-known process of preservation (of meat), the principal modern novelty being Dr. Morgan’s plan of injecting the saline solution into the arterial system – the principal objection to which has been that the meat so treated has been over-salted.” (Sydney Morning Herald, 1 March 1870, p4)
The brine mix that Mr. Morgan suggested was 1 gallon of brine, ¼ to ½ lb. of sugar, ½ oz. of monophosphoric acid, a little spice and sauce to each cwt of meat. (Smith, E, 1873: 36)
Seventeen years later after Smith met Mr. Morgan at the Society of Arts meeting, in 1871, Yeats reports on a certain “Professor Morgan in Dublin, who has proposed a method of preservation by injecting into the animal as soon as it is killed, a fluid preparation, consisting, to every hundredweight of meat, of one gallon of brine, half a pound of saltpetre, two pounds of sugar, half an ounce of monophosphoric acid, and a small quantity of spice.” (Yeats, J, 1871: 225)
The plan was widely tested at several factories in South America and by the Admiralty, who had reported that they had good results from the technique. (Yeats, J, 1871: 225, 226)
It was in all likelihood the same Morgan that Smith reports on who, by 1871, became a professor in Dublin. One interpretation of the Yeats report is that Morgan, by this time, abandoned his arterial injection method for a more general injection into the muscle. It is also possible that Yeats simply is not concerned with a detailed process description.
Notice, as a matter of interest that he used the same basic brine mix of salt, water, saltpeter, sugar, monophosphoric acid and spices. This, together with the similarity in surname makes it quite certain that Mr Morgan and Prof. Morgan is the same person. In itself, this is an example of perseverance! In 1854 his arterial injection was met with scepticism where Yeats reports in 1871 that the Admiralty viewed his improved method with great interest.
The concept of arterial injection was not new. By the time Morgan demonstrated it to the Society of Arts, on April 13, 1854, it may have been as old as 150 years, used for embalming corpses for the purpose of medical studies. This invention is credited by some to the Dutch physician, Frederik Ruysch. (1638 – 1730). He injected a preservative chemical solution, liquor balsamicum, into the blood vessels, but his technique was unknown for a long time. (Bremmer, E.; 2014)
British scientists who used arterial injection and from whom Morgan could have learned the system were the Hunter brothers William (1718–1783) and John (1728–1793) and their nephew, Matthew Baillie (1761–1823). The injection was into the femoral arteries. They all injected different oils, mainly oil of turpentine, to which they added Venice turpentine, oil of chamomile, and oil of lavender. Vermillion was used as a dye to create a more life-like skin colour, but would also have added preservation to the final solution. (Bremmer, E.; 2014)
There is a reference from 1837, on an essay delivered on the operation of poisonous agents on the living body by Mr. John Morgan, F.L.S Surgeon to Guy’s Hospital. (1837; Works on Medicine) The same publication contains an article by Dr. Baillie, M.D. on the morbid anatomy of some of the most important parts of the human body. John Morgan was definitely well familiar with arterial injection. Not only due to the fact that he was a contemporary of Baillie, but demonstrator of anatomy at the private school near Guy’s Hospital. (http://livesonline.rcseng.ac.uk/biogs/E000398b.htm)
Despite the fact that I can not locate a single reference, it is not unlikely that he was the father of Dr. John Morgan (Circa 1863), a professor of anatomy at the University of Dublin. A process of arterial injection is described that was used by Dr. John Morgan from the University of Dublin. ” John Morgan, a professor of anatomy at the University of Dublin in Ireland, formally established two principles for producing the best embalming results: injection of the solution into the largest artery possible and use of pressure to push the solution through the blood vessels. He also was among the first to make use of a preinjection solution as well as a controlled drainage technique. Morgan’s method required that the body is opened so the heart was visible, then an 8-inch pipe was inserted into the left ventricle or aorta. The pipe was connected to yards of tubing ending in a fluid container hung above the corpse. The force of gravity acting on the liquid above the body would exert about 5 pounds of pressure, adequate to the purpose of permeating the body.” (Wohl, V.) This process described here is applied, not to the preservation of animal carcass, but for embalming a human body! It is, however, the exact same process that he demonstrated years earlier in London to Smith at the Society of the Arts meeting on 13 April related to carcass preservation.
From the process description, it is clear that we have finally identified the Morgan, father of the arterial injection method in meat curing as Dr. John, professor of anatomy at the University of Dublin, son of Dr. John Morgan, Surgeon to Guy’s Hospital. The original inventor of the system was the Dutch physician, Frederik Ruysch and the application was embalming.
An 1866 article in the Launceston Examiner reports that Mr. Davis, from Adelaide, bought the patent from Dr. Morgan. Mr. Davis took up “premises at Town Marie, on the Bremer River, about six miles from Ipswich” and the operation of curing commenced.
The 1963 Griffith marketing publication they say that they did not invent arterial injection, but developed in further and I assume they are referring to the fact that they did not apply it to carcass preservation, but to injection and curing of hams and shoulders. They also list stitch pumping or bone pumping as it was also called and spray pumping of hams. Spray pumping was also done along the bone in the ham and I assume they are talking about the needle having small spray opening on the side, as is the case with most modern injector needles.
Dr. John Morgan from the University of Dublin must rightfully be credited as one of the pioneers of meat injection, as a progression of an original development from the world of mummification, invented by the Dutch physician, Frederik Ruysch. The concept was “in the air,” so to speak and in an 1868 publication, On Food, Letherby says that “saline substances such as saltpeter, acetate of ammonia, sulfite of potash, or soda, muriate of ammonia (sal ammoniac or ammonium chloride) etc, were being injected into fresh meat for the purpose of preservation with several patents pending by Long (1834), Horsley (1847), Murdock (1851) and others. (Letheby, H., 1870)
It is reported today by some bacon curers that they use the dry-curing in conjunction with injection. In this case, the meat is injected with approximately 10% saturated brine solution and the injected meat is then treated the usual way in the application of dry-salt-cure. There is a record showing that the famous Harris from Calne in the United Kingdom used injection with their dry cured bacon from 1843.
After it has been dry-cured, the meat is smoked at a temperature of not higher than 38 deg C (100 deg F) in order to prevent nitrate burn which presents itself as green spots that appear on the meat. Care should also be taken if these products are stored to prevent damage from insects such as cheese skippers, mites, red-legged ham beetles, and larder beetles. (Hui, Y. H., 2012: 540)
Brine-soaking followed dry-salt-curing. Again, note that dry or wet curing is defined by what the meat if left in to cure and not what is injected into the meat. The process is also relatively slow and meat pieces are placed in a mixture of salt, saltpeter, and water. It is important to take temperature into account since spoilage may occur before the brine had a chance to penetrate the meat. (Hui, Y. H., 2012: 540)
An 1830 description of a “wet cure” survived where a farmer describes the dry cure method as “tedious.” He credits Europe as the birthplace of the wet-cure method. One of the benefits of this simple system is that it can be used for mutton and beef also. The down-side is that it is more expensive than dry-cure, but the wet cure could be re-used and taking everything into account, would work out cheaper in the long run than dry-cure. (The Complete Grazier, 1830: 304)
This re-using of the brine would turn out to become the cornerstone of the industrial revolution for bacon curing and the country credited for this development is Ireland. Before we get to that, we have to first look at barrel pork.
Barrel pork was an easy way to cure pork that involved liquid brine. It had the benefit that it could be put in barrels, loaded onto a wagon or a ship for transport and cure in transit. It also had the benefit of being stored in the cure and being safe from flies and other insects.
In the 1800s, this was the main way that the packing plants in the USA exported pork to England as bacon. There are many accounts in newspapers of the time where advice is given to the bacon producers on how to make sure that the meat arrives in England unspoiled. One of the main points was the importance of using good, new wood for the barrels.
A 1776 description is given on how barrel pork was produced.
“After the meat has cooled < probably after the hair was removed >, it is cut into 5 lb. pieces which are then rubbed well with fine salt. The pieces are then placed between boards a weight brought to bear upon the upper board so as to squeeze out the blood. Afterward, the pieces are shaken to remove the surplus salt, [and] packed rather tightly in a barrel, which when full is closed. A hole is then drilled into the upper end and brine allowed to fill the barrel at the top, the brine being made of 4 lb. of salt (1.8kg or 10%), 2 lb. of brown sugar (0.9kg or 5%), and 4 gallons of water (15L or 84%) with a touch of salt-petre. When no more brine can enter, the hole is closed. The method of preserving meat not only assures that it keeps longer but also gives it a rather good taste.” (Holland, LZ, 2003: 9, 10)
Again, notice the brine make-up of salt, saltpeter, sugar mixed with water. The role of the sugar was to break the hard salt taste.
Barrel pork would remain an important curing method throughout the 1700’s and would make a spectacular return almost a 100 years later when pressure pumps were introduced to inject the brine into the meat through needles. A plank would be run across the barrel opening. The meat is placed on the plank for injection with between one and three needles. The three needles are fed brine through a hand pump that would pump brine directly from the barrel. The barrel is half filled with brine. After the meat has been injected, it is pushed off the plank, to fall into the brine which acts as a cover brine. It would remain in the cover brine the prescribed time before it is removed and smoked.
We can now return to the 1830 account of wet-curing where we identify important developments in brining technique. The farmer who wrote down the brining technique suggests that the brine mix must be boiled over a gentle fire for the impurities to rise to the top before these were skimmed off and the brine allowed to cool down. (The Complete Grazier, 1830: 304)
When it is cooled down, the brine is poured over the meat so that the meat is completely submerged. Meat from small pigs is kept in the brine for three to four days and longer. An older pig may require one, two, or three days longer. (The Complete Grazier, 1830: 304)
If the meat is intended for hams, it must be left in the brine for two days. At the end of the curing time, rub with pollard (a by-product from the milling of wheat, like bran) and cover with a paper bag to keep flies away. In warm weather, make sure that the blood is all drained from the meat and the meat is rubbed with fine salt before the brine is poured over. (The Complete Grazier, 1830: 304)
Remember that wet-cure is more expensive than dry cure unless the brine is re-used. Our farmer states that brine is re-used “with advantage”. Before it is re-used, the old brine must be boiled first and water and the other ingredients must be added proportionately. (The Complete Grazier, 1830: 304)
It is this old brine or re-used brine that became the cornerstone of the industrial bacon curing plants in Denmark and which they call the “mother brine”. Needle injection of meat along with the faster curing action of the mother brine would become the key feature of curing plants in Denmark and would later be adopted by factories around the world. It was the fastest way of producing bacon and was remarkably effective. The invention of what became known as tank curing or mild cure was, however, not Danish, but Irish!
Oake’s invention: The Industrialization of Bacon Curing
When I started looking into the different aspects of curing that is united in Oake’s invention, I wondered what exactly did Oake invent? It is possible that the entire process of handling the animal from killing to actual bacon is his claim to fame and not any one particular part of the invention. As is so often with great inventors, they often take information which is out there and combines it in new and useful ways. This may be the exact legacy of Oake. He thought through the entire process, packaged it, named it and then advocated it. To the Irish belongs the credit for this!
Let us return to the 1930 reference in the Complete Grazier which we looked at above. They wrote that the brine mix must be boiled over a gentle fire for the impurities to rise to the top before these were skimmed off and the brine allowed to cool down. They reported that such brine is re-used “with advantage”. Before it is re-used, the old brine must be boiled first and water and the other ingredients must be added proportionately. This may actually be a report on the process invented by Oake which may take the invention by Oake back to 1830.
Lets also again look at the description of barrel pork from 1776. “After the meat has cooled,” probably after the hair was removed, “it is cut into 5 lb. pieces which are then rubbed well with fine salt. The pieces are then placed between boards a weight brought to bear upon the upper board so as to squeeze out the blood. Afterward, the pieces are shaken to remove the surplus salt, [and] packed rather tightly in a barrel, which when full is closed. A hole is then drilled into the upper end and brine allowed to fill the barrel at the top, the brine being made of 4 lb. of salt (1.8kg or 10%), 2 lb. of brown sugar (0.9kg or 5%), and 4 gallons of water (15L or 84%) with a touch of salt-petre. When no more brine can enter, the hole is closed. The method of preserving meat not only assures that it keeps longer but also gives it a rather good taste.
The next element Oake improved on was the actual place where the curing is done. Instead of wood, Oake designed special curing tanks and moving away from barrels with its obvious drawback of using wood to cure bacon in and the accompanying problem of insects that inhabit the wood.
The next major improvement was in the design of the actual brine. The most interesting aspect of his cure is his use of sal prunella. He used a very pure form of saltpeter. Not the kind that is used as fertilizer, but the kind that is used to make black powder. The Irish were, at the time of Oake’s invention, actively experimenting with preservatives in their medical universities. I believe the invention was in part done, because of knowledge they developed on how to preserve human bodies for the purpose of gaining medical knowledge or training physicians. Oake was probably trained by men, proficient in the morbid arts.
Apart from the use of sal prunella, Oak used a position proposed by none other than Liebig that the preserving power of salt was not due to the chemistry of salt or some secret power contained in it but due to the fact that it drew out the moisture from meat. Oake explains that it was believed that salt drew out the albumen from the meat and it is when water comes into contact with the albumen that putrefaction sets in. The essence of the invention, according to him, is that the meat is cured while the albumen remains in the meat and does not taste as salty as dry cured bacon.
Oake’s invention rests, then, on the stepwise process, the use of specially designed tanks and his scientific description of the preservation process which was made possible by his training as a chemist. This gave his system instant credibility because he was able to describe it in the scientific language of our time.
Wet-curing in combination with injection (brine cure – with pumping)
In Ireland, just sometime, probably between 1830 and 1837, a wet curing method was invented by William Oake. (Tank Curing was invented in Ireland) A major revolution took place in Denmark in 1887/ 1888 when their sale of live pigs to Germany and England were halted due to the outbreak of swine flu in Denmark. The Danes set out to accomplish one of the miracle turnarounds of history by converting their pork industry from the export of live animals to the production of bacon (there was no such restriction on the sale of bacon). This turnaround took place in 1887 and 1888. They used the cooperative model that worked so well for them in their abattoirs namely the cooperative.
They were amazingly successful. In 1887 the Danish bacon industry accounted for 230 000 live pigs and in 1895, converted from bacon production, 1 250 000 pigs.
One would expect that the Irish system of curing was imported to Denmark then. This is however incorrect. The first cooperative bacon curing company was started in Denmark in 1887. Seven years earlier, in 1880, the Danes visited Waterford and “taking advantage of a strike among the pork butchers of that city, used the opportunity to bring those experts to their own country to teach and give practical and technical lessons in the curing of bacon, and from that date begins the commencement of the downfall of the Irish bacon industry. . . ” (Tank Curing was invented in Ireland)
This is astounding. It means that they had the technology and when the impetus was there, they converted their economy. It also means that Ireland not only exported the mild cure or tank curing technology to Denmark but also to Australia, probably through Irish immigrants during the 1850s and 1860s gold rush, between 20 and 30 years before it came to Denmark. Many of these immigrants came from Limerick in Ireland where William Oake had a very successful bacon curing business. Many came from Waterford. A report from Australia sites one company who used the same brine for 16 years by 1897/ 1898 which takes tank curing in Australia to well before 1880 which correlates with the theory that immigrants brought the technology to Australia in the 1850s or 1860s.
One further note about the invention of tank curing by Oake from Ireland. He apparently was a chemist and his invention had as much to do with the brine makeup as it had to do with the fact that tanks were used and the brine re-used. Morgans work shows clearly that curing brine was a priority in Ireland in the mid-1800s. The possibility that Oake and Morgan interacted and possibly influenced each other is a tantalizing likelihood that emerges from the data.
It was Denmark, however, who continued to expand on the tank curing system or mild cured system, as it was called, using a combination of stitch pumping and curing the meat in curing tanks with a cover brine. (Wilson, W, 2005: 219) Brine consisting of nitrate, salt and sugar were injected into the meat with a single needle attached to a hand pump (stitch pumping). Stitch pumping was either developed by Prof. Morgan, whom we looked at earlier or was a progression from his arterial injection method.
The meat was then placed in a mother brine mix consisting of old, used brine and new brine. The old brine contained the nitrate which was reduced through bacterial action into nitrite. It was the nitrite that was responsible for the quick curing of the meat.
Denmark was, as it is to this day, one of the largest exporters of pork and bacon to England. The wholesale involvement of the Danes in the English market made it inevitable that a bacon curer from Denmark must have found his way to Calne in Wiltshire and the Harris bacon factories. The tank-cured method, as it became known, was adopted by C & T Harris.
A major advantage of this method is the speed with which curing is done compared with the dry salt process previously practiced. Wet tank-curing is more suited for the industrialisation of bacon curing with the added cost advantage of re-using some of the brine. It allows for the use of even less salt compared to older curing methods.
The question comes up if we have corroborating evidence that Denmark imported the Irish technology in 1880? Clues to the date of the Danish adaption come to us from newspaper reports about the only independent farmer-owned Pig Factory in Britain of that time, the St. Edmunds Bacon Factory Ltd. in Elmswell. The factory was set up in 1911. According to an article from the East Anglia Life, April 1964, they learned and practiced what at first was known as the Danish method of curing bacon and later became known as tank-curing or Wiltshire cure.
A person was sent from the UK to Denmark in 1910 to learn the new Danish Method. (elmswell-history.org.uk) The Danish method involved the Danish cooperative method of pork production founded by Peter Bojsen on 14 July 1887 in Horsens. (Horsensleksikon.dk. Horsens Andelssvineslagteri)
The East Anglia Life report from April 1964, talked about a “new Danish” method. The “new” aspect in 1910 and 1911 was undoubtedly the tank curing method. Another account from England puts the Danish invention of tank curing early in the 1900s. C. & T. Harris from Wiltshire, UK, switched from dry curing to the Danish method during this time. In a private communication between myself and the curator of the Calne Heritage Centre, Susan Boddington, about John Bromham who started working in the Harris factory in 1920 and became assistant to the chief engineer, she writes: “John Bromham wrote his account around 1986, but as he started in the factory in 1920 his memory went back to a time not long after Harris had switched over to this wet cure.” So, late in the 1800s or early in the 1900’s the Danes imported the Irish system and practiced tank-curing which was brought to England around 1911. The 1880 date fits this picture well.
It only stands to reason that the power of “old brine” must have been known from early after wet curing and needle injection of brine into meat was invented around the 1850s by Morgan. Before the bacterial mechanism behind the reduction was understood, butchers must have noted that the meat juices coming out of the meat during dry curing had special “curing power”. It was, however, the Irish who took this practical knowledge, undoubtedly combined it with the scientific knowledge of the time and created the commercial process of tank-curing which later became known as Wiltshire cure.
The composition of the brine changed around 1915 by the direct addition of sodium nitrite. Multi-needle injectors and vacuum tumblers are commonly used in combination in modern meat curing plants around the world.
It is generally accepted that these developments took place in the mid to late 1900’s, but an interesting US patent (number 23,141) was awarded to L. M. Schlarb from Allegheny, Pennsylvania on 3 June 1901 directly related to injection and vacuum machines for meat curing. (Journal of the Society of Chemical Industry; 1902: 269)
The process is described as “injecting brine and carbon dioxide under pressure into the meat by means of suitable needles connected to a tank containing the brine and carbon dioxide, the pressure in the tank being about 2 atmospheres.” The nozzles it talks about maybe the three needle injectors that were used until the middle of the 1900’s and the unique aspect of the patent was the use of brine in conjunction with carbon dioxide. (Journal of the Society of Chemical Industry; 1902: 269)
The next bit is fascinating as it is possibly the earliest recorded date of the use of a vacuum machine in meat processing. The patent is described in a journal article that “the meat is now placed in a vessel from which the air is exhausted, and brine is then allowed to flow in. The meat is allowed to remain in the brine for about 10 hours, and may then be subjected to the action of carbon dioxide under pressure.” If one removes the presence of carbon dioxide, it is then reasonable to assume that a vacuum machine has been in use in one shape or another to facilitate the diffusion of brine into meat, as early as 1901 and probably earlier. (Journal of the Society of Chemical Industry; 1902: 269)
Over the next 60 years, the multi-needle injector became bigger, with more needles until the present machines were being produced from the mid-1900’s. Tumbling machines, as we know it today has been in use from the early 1970’s.
The biggest development in commercial curing plants of the last decade is undoubtedly the introduction of what we call the grid system. According to this method, grids or bacon moulds are used to give the bacon a regular shape. The meat is normally wrapped in banking paper before it is placed in the moulds and in one form or the other, an enzyme, Transglutaminase, is incorporated added to the product. The main purpose of this is to achieve higher slicing yields, but in reality, it also accounts for lower smoking losses. A detailed treatment of this method can be found at The Best Bacon System on Earth. I am inviting producers to who are interested to interact with me on the process as long as developments will be used for our mutual benefit.
As far as brine technology is concerned, a host of brines has seen the light which claims to be natural and nitrite-free. I remain very skeptical about these and refer you to Mechanisms of Meat Curing. The only compound that I have ever tested that accomplish nitrite or nitrate free is sal ammoniac and tests are still underway to develop this into a commercially viable proposition that will be accepted by the public who have demonstrated an aversion against the use of ammonia in curing, more so than against nitrite.
This review is done from the perspective of a commercial mainstream high throughput bacon plant. It, however, paints a rich picture and most of what is regarded as “artisan” today has been the way that large throughput factories of yesteryear have done it. In years to come, how bacon was cured even when we embarked on our current bacon project in 2008 will be regarded as “artisan curing” as we have seen the transition to moulds or grid curing over the last 10 years.
Consumer demands, perceptions and technology will remain the driving force behind this fascinating industry. Many aspects will have to be added to this review article such as change to health concerns and this changed the methods and ingredients over the years. As time allows, I will add these.
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