Bacon and the art of living 18: The history of curing

June 1892

Dear Dad,

043-Tower_bridge_works_1892

Today I arrived in London.  What more can I say.  London!

You taught me courage.  As a boy you encouraged me and Ava to explore the cliffs of Table Mountain.  You were never afraid to let us face cold and hunger, knowing that it would only make us strong.  You allowed me to try new things, as long as it was done from the conviction of my heart.  It was after you had a stroke that I have seen real courage.

Chief magistrate in Cape Town for so many years and yet, after your stroke, when you lost your speech and ability to read, you continued to go to work.  You asked the court to allow you to oversee the upkeep of the grounds.  Reluctantly they granted your wish.  Not that they doubted your ability to do the work, but thinking that it may not be “fitting”.  Your only desire was to work.  The office from where you performed your duties became your castle and I loved visiting you there after school. (1)

In so many respects I do what I do because of you.  You taught us no matter how dark the moment, the greatest joy we can have is the actual voyage.  That if we look carefully, we will find great joy in life despite circumstances.  There will always be gardens to tend, mountains to climb and valleys to hike through.  What greater glory is there than life itself!

Oscar writes that setting up the Cape Town factory is not an easy task.  Farmers who form the bulk of our investors find it hard to understand the meat trade.  It is not easy!

I have received word that David Graaff and his team are also beset by problems.  In his mind he is about to loose everything.  Their company’s success is grounded in both their close proximity to the abattoir in Cape Town and the Cape market.  It has worked well for them and afforded them untold wealth.

The old railway station at the foot of Adderley Street is bursting at the seams.  Daily commuters between Cape Town and Simons Town increased.  The discovery of gold and diamonds in the interior are putting even more pressure on the small terminus.  Everybody can see it must be expanded, but on the one side is the Castle of Good Hope and the other side, the sea, leaving only one possible direction of expansion.

Rumors are rife that the city of Cape Town intends expropriating the site where Combrinck & Co is located for the expansion. (2)  (Simons, P., 2000:  29, 30)  Ava tells me that David is in great deal of distress.  If this happen, the successful business model of being located in close proximity to the suppliers of the meat and the consumer will be challenged.

deboning room
The cutting-up room at the Zillmere Bacon Factory. From Queensland Agricultural Journal, 1925, collection of Fryer Library, UQ.

Curing technology – a historical review

On the steam boat from Denmark I had time to reflect on my Danish adventure.  As the days went by, in my mind it was like fog clearing.  I started to see the progression of curing technology at the heart of bacon processing.  In so many respects I am fortunate to be away from Cape Town and the pressures of dealing with investors, buying of land and constructing a suitable site for our bacon curing venture.  It allows me the opportunity to focus and learn.  On the other hand I miss being there to support Oscar, Willem, James and Roy.

The story of curing is becoming clear and in my mind the worry about our business is easily overrun by the excitement of piecing this engaging history together.  It helps me understand a subject that I did not know exist a year ago.

Dry-salt-curing

Reflecting on everything I have learned, I realise that the first form of curing was probably dry-curing with salt only.  Humans must have discovered very quickly that certain salt, for example sea salt or bay salt, had the ability to turn pork meat reddish/ pinkish and prevented it from turning brown.

The practice of salting meat existed in many cultures including the Far East, the Romans, the Celts and the Gauls.  Cultures like the Romans and the Far East may not even have had direct contact with each other at the time when curing meat was first practiced by them. (economist.com)

I have learned that most salt have some nitrite or nitrate in it.  Sea salt have all the minerals and chemical elements of the earth washed into it by rain.  Some cultures discovered particular salts, mined from specific locations in dry regions had far more of this “special power”, endowed with a peculiar bitter taste and a greater ability to bring about this reddish/ pinkish colour.

This salt came to be known as saltpeter.

This same saltpeter had great use in the production of explosives such as gunpowder and had very productive applications as a fertiliser.  It became a widely traded commodity and companies were created around the world who specialised in not just mining and shipping it, but later in manufacturing it.  (Hui, Y. H.,  2012: 540)

The salt is 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)

Cato the Elder

The first recorded account of pork curing is found from Cato the Elder who wrote in 160 BCE.

I discovered this work at the University of Copenhagen.  In his Latin work, De Agricultura (On Farming), this Roman statesman and farmer gives an ancient recipe for curing pork.

“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)

A professor who pointed me to the work speculated that Cato may have imitated a process whereby ham’s are smoked over juniper and beech wood.  The process was probably imported by the Roman gourmets from none other than Germania.

Dry-salt-curing in combination with injection

In Denmark it was Andreas’ dad who taught me about a certain Mr Morgan in England who invented the technique of injecting a liquid brine into the meat.

The motivation was to increase the rate of curing in order to reduce the time required for processing.  The initial drive was not for high volume, industrial processing plants as Jeppe’s curing plant, but due to the fact that pork meat spoils quickly if the temperature is not consistently low.  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.  Before I tell you more about Mr Smith, 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 account the events of “Mr Morgan [who] devised an ingenious process by which the preserving material, composed of water, saltpetre, 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.

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, 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 probably the same Morgan that Smith reports on who by 1871 became a professor in Dublin.  He has by this time apparently abandoned his arterial injection method for a more general injection into the muscle, even though this system still prevails in many butcheries across the world.

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 me quite certain that Mr. Morgan and Prof. Morgan is the same person.  In itself this is an example in perseverance!  In 1854 his arterial injection was met with skepticism where Yeats reports in 1871 that the Admiralty viewed his improved method with great interest.

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.

The meat is then smoked at a temperature of not higher than 38 deg C (100 deg F) in order to prevent nitrate burn which present 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

Brine-soaking probably followed dry-salt-curing.  The process is relatively slow and meat pieces are placed in a mixture of salt, saltpeter and water.  (Hui, Y. H.,  2012: 540)

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)

I came across a 1830 description of a “wet-cure.”  A farmer describes the dry cure method as “tedious.”  He credits Europe as the birth place 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 Denmark.  Before we get to that, we have to first look at barrel pork.

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 1800’s, 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 arrive in England unspoiled.  One of the main points was the importance of using good, new wood for the barrels.

I red an account at the University of Copenhagen where 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. Afterwards 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 in 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 act as a cover brine.  It would remain in the cover brine the prescribed time before it is removed and smoked.

Boiling of the brine

founders
The original founders of the St. Edmunds Bacon Factory are shown in this old print of the laying of the factory’s foundation stone in 1911.

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 suggest that the brine mix 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 are 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. (The Complete Grazier, 1830:  304)

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.

I have explained this system in great detail in my previous letter to the children.

Dad, the more I think about it, the more I am convinced that the Danes knew well before 1891 bacterial reduction changes nitrate (NO3-) to nitrite (NO2-) in the mother brine.  They did not want to use sodium nitrire directly due to the very negative connection attached to sodium nitrite on account of its lethal toxicity.  I am convinced they knew this reduction took time and if they use an old brine and only top it up with salt and saltpeter, that they were applying nitrite directly to the curing process.

Wet-curing in combination with injection

stitch injection elmswell-bacon-factory

The Danes use wet curing and injection together.  They inject a mixture of salt and saltpeter into the muscle and leave the injected muscle in a mother-brine as the cover brine.  This actually gives them the best of both worlds.

The nitrite which they get from the mother brine would immediately go to work and start curing the meat while the nitrate injected as saltpeter (potassium nitrate) would, over time, be reduced to nitrite and continue to do the curing work even long after is has been removed from the cover-brine.

The method is simply ingenious and the only thing more effective would be if we directly add sodium nitrite to the brine in a fixed proportion.  At this point sodium nitrite is however very expensive and regarded with great skepticism by the general public who sees it as a drug for heart conditions and as a specialty product used in the dye industry.

Dad, I am excited to make my way to Calne, close to the ancient town of Bristol where I will meet the Harris family from C. & T. Harris (Calne) Ltd.

Andreas told me to be prepared to hear quite a few stories on refrigeration and how this invention propelled the Harris family to prominence in the bacon world.  They are legend in the bacon world and their bacon is famed as being the best on earth.

I can hardly wait.  London is big and busy.  I have never seen so many people in one place before, but the expectation and excitement of meeting the Harris family very soon is something that I can not put in words.  They have achieved legendary status with their Wiltshire cure.

I promise to write more when I get to Calne!

Love to Mom, Ava and the kids!  Take care of yourself, Dad!  I miss you a lot!

Eben
——————

(c) eben van tonder

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Notes:

Note 1:  My dad started his career as a magistrate in the small highveld town of Evander.  I was born in Bethal, not far from there.  He was transferred to Vanderbijlpark a year before I went to school and later became chief magistrate in Meyerton, in the Vaal Triangle.  He had a stroke when I was 14, leaving him without the ability to read, write or speak.  The office in Vandebijlpark graciously allowed him to work as overseer of the cleaning staff.  He passed away in 1990 after a car accident.

My mom continued to work as clerk of the civil court in Vanderbijlpark for many years.  I regularly visited him in the small office in the basement.  He would walk with me to a cafe close by to get me a cool-drink.  Almost every time I would get a lecture (in his way of speaking and gesturing) about the fact that true happiness is found inside of us, despite our circumstances.

I can not remember a time when he did not have a bible open on his desk, learning to read from it.  Passages that deals with joy and comfort in the midst of great suffering was underlined in red and blue and highlighted.  My dad was an amazing man!

Note 2:  David and his team knew that their location was under threat.  The possibility of expropriation has been whispered to them unofficially by the general manager of the Railways, Charles Bletterman Elliot, who also happened to be assistant commissioner of Crown Lands.   In April 1893 Charles approached David Graaff personally and informed him that a firm decision has been made by the Cape Government Railways to expand the station in the direction of the slaughtering site and the location of Combrinck & Co. (Simons, P., 2000:  29, 30)

Note 3:  1 and 1/2 – 2 days per pound or half a kg of meat at 2 – 3 deg C.  (Hui, Y. H.,  2012: 540)

References:

The Complete Grazier.  1830.  Fifth edition.  paternoster Row.  Baldwin and Cradock

Holland, LZ. 2003. Feasting and Fasting with Lewis & Clark: A Food and Social History of the early 1800’s. Old Yellowstone Publishing, Inc.

Hui, Y. H..  2012.  Handbook of meat and meat processing.  Second edition.  CRC Press.

Simons, Phillida Brooke. 2000. Ice Cold In Africa. Fernwood Press

Smith, Edwards. 1873. Foods. Henry S King and Co.

Yeats, J. 1871. The technical history of commerce; or, Skilled labour applied to production. Cassell, Petter, and Galpin

http://www.economist.com/node/8345876

 

 

Images

Figure 1:  The Tower of London, 1892, from http://ponygurl.wikispaces.com/

Figure 2:  Cutting plant, http://www.queenslandplaces.com.au/zillmere

Figure 3:  Founders of bacon plant:  http://www.elmswell-history.org.uk/arch/firms/baconfactory/article2.html

Figure 4:  Stitch pumping, http://www.suffolkheritagedirect.org.uk/resources/tours/made-in-suffolk.html

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