Dear Tristan and Lauren,
It is autumn. It mirrors my mood as I am writing to you today. As much as I am excited every Monday morning about what is on the menu that week, I am also frustrated because I know that I must get done here so that I can get home. The value in knowledge is not in the knowing, but in the doing.
Everything that I know and learn must translate into products that are sold to consumers who are willing to pay for the goods. If this does not happen, I am no more than a man engaged in mind games. What I learn and the skills I acquire must change into profit for a business.
On the other hand I also know, as another good friend that I met in Denmark has told me, if I have 5 years left on earth and I have to do something new, it will be best if I spend the first four years preparing for it.
Working through the complexities of the matters at hand will have a reward in my life, but also in yours if you would choose to follow on this exciting path. It really seems like the most complicated industry in the world.
Every day is spent on solving a giant mathematical equation.
The friends name is Martin Sauer. His dad has been in the pork business all his life and has travelled extensively through Africa. I was telling Martin one day all that Jeppe and Andreas has been teaching me. Martin laughed and said that I will spend a lifetime on these matters and must not try and remember everything. When I get back home I will have ample time to go over my notes. More than this, I may learn many new things that may seem to contradict some of the things that I’ve learned. I am looking forward to meet his father because I heard that he met Livingston.
It was a strange thing that Martin told me. The thing about learning things that may seem contrary to what I was taught at first. What was even stranger was that the following Monday, Jeppe told me that this was true when it comes to saltpetre and nitrite. Remember that I told you that it is the key ingredient in curing bacon?
This statement is not entirely accurate. The real magical ingredient in bacon is salt!
So opened up to me another vast world. The world of salt.
At night, after supper, we still read Foods by Edward Smith, written in 1867. He writes, “the oldest and best known preserving agent is salt, with or without saltpetre.” (Smith, E, 1867: 34) (1)
Remember the quote from the American Encyclopedia of 1858. It said that “Very excellent bacon may be made with common salt alone, provided it is well rubbed in, and changed sufficiently often. Six weeks in moderate weather, will be sufficient for the curing of a hog of 12 score.” (Governor Emerson . 1858: 1031) (1)
So Jeppe started last Monday, during my lunch time lessons to discuss the matter of salt. As was the case with saltpetre, a world started to open up for me that I did not know existed.
That white substance that I used so many times back in Cape Town and now, here in Denmark, without giving a second thought as to the nature and the power inherent in it.
As I could have guessed, the story of the use of salt goes back much further even than the story of humanity.
It is likely that the Neanderthals (2), some 125 000 years ago, that ancient and extinct subspecies of homo sapiens (Wikipedia, Neanderthal) were the first to use salt to preserve meat. They probably prepared and stored food “at locations near readily available salt and may well have learned to preserve food with it.” (Bitterman, M, 2010: 16).
There is evidence that using salt to preserve has been practiced since before the last ice age, some 12 000 years ago. Salt deposits in the hills of Austria and Poland, the shores of the Mediterranean and Dead Sea, the salt springs and sea marches across Europe and Asia would have provided salt to cultures across the world. (Bitterman, M, 2010: 16) To this list I can add the great salt pans and salt springs across our great African land.
It is doubtful that the use of the salt was very sophisticated.
The next step in the development of the technique of preserving meat was curing (2). Adding salt to meat evolved into an art.
A Dutch legend says that the curing of herring was invented by Willem Beukelsz around the early 1300’s. Whether this is entirely true or not, we know for a fact that the Cossacks produced cured caviar. The Romans used a sauce called garum on their food. Garum was made among other with brine (salt solution). (Laszlo, P, 1998: 5, 7, 11)
Marcus Porcius Cato (234 BCE – 149 BCE) or Cato the Elder was a Roman statesman, who devoted himself to agriculture when he was not engaged in military service. (Wikipedia, Cato_the_Elder) He recorded careful instructions in dry curing of hams. (Hui, YH, et al, 2001: 505)
Curing took meat which we culled from nature and brought it into culture. (Laszlo, P, 1998: 14) It turned the art of preserving into an expression of community and “togetherness” by transforming “preservation of food” into culinary delights of great enjoyment.
As our way of life evolved, we domesticated our food sources. We started with the fig, probably many years before we did the same to grain. Archaeologists found domesticated figs dating back to 9400 BCE. Sheep were domesticated around 8000BCE, cattle and pigs around 7000 BCE. (Bitterman, M, 2010: 17)
In the time period 15 000 to 5000 BCE, we developed a need for salt for ourselves and our domesticated livestock. The livestock had to supplement their diet with salt and we needed it for curing and preserving foods, tanning hides, producing dyes and other chemicals and for medicine. “We evolved with a physiological requirement for salt; our culture was born from it. Access to salt became essential to survive. Salt localized groups of people.” (Bitterman, M, 2010: 17)
The Danes are great traders and Copenhagen is a key centre for trading Saltpeter.
There is evidence that by 1,200 BCE, another great traders civilization of ages past, the Phoenicians, were trading salted fish in the Eastern Mediterranean region. (Binkerd, E. F.; Kolari, O. E. 1975: 655–661) Saltworks were one of the main features of their settlements in Labanon, Tuniaia, Egypt, Turkey, Cyprus, Crete and Sicily.
By 900 BCE, salt was being produced in ‘salt gardens’ in Greece and dry salt curing and smoking of meat were practiced and documented. (Binkerd, E. F.; Kolari, O. E. 1975: 655–661)
Ancient records of 200 BCE tell us that the Romans learned how to cure meat from the Greeks and further developed methods to “pickle” various kinds of meats in a brine marinade. Salting had the effect of reddening the meat and the report of this observation became the first recorded record of the colour effect of saltpeter. (Binkerd, E. F.; Kolari, O. E. 1975: 655–661)
Phoenician ships spread the technology of salt making across the Atlantic, to Spain and as far north as England. India, China, Japan and Africa developed their own salt industries.
Hardly a region on earth or a civilisation could be found who did not produce salt. Salt was taxed, traded, used as currency and consumed on a global scale. (Bitterman, M, 2010: 17 – 25)
The domestication of our food sources, the need for preservation and the technology to produce salt developed hand in hand as features of the spread of culture and civilisation with humans.
What was the mechanism that made salt such an effective preservative?
In order to understand the mechanism of salts preservative power, we must first understand salts composition.
Before the 1700’s, scientist could not distinguish between the different alkali metals. Sodium and potassium were often confused. Potassium was produced artificially by slowly pouring water over wood ashes and then drying the crystal deposits. Some of these metals were also found naturally on the edges of dried lake beds and mines and sometimes at the surface of the ground.
Henri-Louis Duhamel (1700 – 1782) realised that certain metals had similar characteristics. He studied samples of salts found in nature and produced by people artificially. This included the study of saltpetre (potassium nitrite), table salt, Glauber’s salt, sea salt and borax. (Krebs, RE, 2006: 51) He discovered sodium carbonate and hydrochloric acid, a solution with a salty taste, in 1736. (Brian Clegg, rsc, chemistryworld)
Humphry Davy, an English Chemist, was the uniquely talented young man who changed history when he isolated sodium and potassium in 1807.
He had the first direct electric current generator at his disposal, the electric battery that Alessandro Volta had invented in Paris in 1800. Davy ran an electric current through caustic soda (sodium hydroxide) and was able to isolate sodium from it. He did the same for potassium, isolating it from potash.
Chlorine was already being produced through electrolysis by the decomposition of sea salt by the electric current. Caustic Soda and chlorine had many applications by the end of the 1700’s.
Fats were processed with caustic soda to produce soap. Fabrics were being bleached with chlorine, a process discovered by Berthollet. (Laszlo, P, 1998: 50)
In 1807, Humphry Davy found that the “muriate of soda” produced by burning sodium in a vessel full of chlorine was chemically identical to salt. (Brian Clegg, rsc, chemistryworld)
Humphry wrote in 1840, “Sodium has a much stronger attraction for chlorine than oxygen; and soda or hydrate of soda is decomposed by chlorine, oxygen being expelled from the first, and oxygen and water from the second.”
“Potassium has a stronger attraction for chlorine than sodium has; and one mode of procuring sodium easily, is by heating together to redness common salt and potassium. The compound of sodium and chloride has been called muriate of soda, in the French nomenclature; for it was falsely supposed to be composed of muriatic acid and soda; and it is a curious circumstance that the progress of discovery should have shewn that it is a less compounded body than hydrate of soda, which 6 years ago was considered as a simple substance, and one of its elements. According to the nomenclature which I have ventured to propose, the chemical name for common salt will be sodane.”
“Common salt consists of one proportion of sodium, 88, and two of chlorine 134; and the number representing it is 222” (Davy, H. 1840: 247)
The importance of this is that the knowledge that the salt used for preserving food is mainly sodium chloride, existed from the early 1800’s.
It was now possible to analyse the nature of sodium chloride and the other kind of salts that exist. The nature of the composition of salt that has been dissolved in water and the interaction between salt and meat and between salt and microorganisms such as bacteria that are present in meat.
It is possible to look at everything that make up sea salt and salt from inland springs and dry salt beds and we can begin to understand and appreciate the effect of salting meat and how it happens that it preserves the meat.
It was found that salt had other metals and compounds of a diverse, but consistent nature. These other elements present in salt that we find naturally on earth, do they impact on the curing process at all? And if so, how? (4)
As I have learned, answering these questions would be very important in order to improve the consistency and the quality of the bacon we cure.
It has been a very busy week-end. Martin took me around the old city. I am excited to learn more about Livingston from his dad since I have heard that Livingston has seen many of the great salt beds and natural salt springs in Africa. So much work has been done by scientists in Europe and America, in India and China. Has there been any discovery in Africa that can help enhance our understanding of the effect of salt on curing in order to improve our processes and procedures and ultimately our products?
I am excited for the new week. Martin agreed to take me along when he is meeting with ship owners who buy their bacon. I hope to learn much from him. He has been trading with many of the Europeans who have moved into the north and central parts of Africa.
I continue to miss you guys. Keep my letters. Read them often. Work hard in school. Help Ava around the house.
Warm greetings, with love!
(1) We have seen how pervasive the occurrence of nitrate is on earth. One expect to find it in every natural salt spring, salt marsh, dry salt lake and in sea water. “Some curing” will take place with almost any natural salt. However, it has been shown that bacon that was produced with either no nitrites or nitrite levels of 15 ppm, “off-flavours were high and increase rapidly. A significant reduction in off-flavours in pork during storage was observed when nitrites were added > 50 ppm.” (Rahman, SM, 2007: 307)
Salt springs, analysed in South Africa contained as little as < 1 mg/ L of Nitrate (H)
This does not correlate with the statement by Smith and the American Encyclopedia about the fact that normal salt was equally successful in curing meat.
Adding salt enhance the flavour, but it also accelerate lipid oxidation, even at low levels of addition. Lipid oxidation leads to off flavour development in meat that does not contain any nitrites. Even a 0.5% addition of sodium chloride significantly increase lipid oxidation when added to restructured pork chops and pork sausage patties following freezer storage. (Pearson, AM, et al, 1997: 269)
(2) ‘The binomial name Homo neanderthalensis – extending the name “Neanderthal man” from the individual type specimen to the entire species – was first proposed by the Anglo-Irish geologist William King in 1864 and this had priority over the proposal put forward in 1866 by Ernst Haeckel, Homo stupidus. The practice of referring to “the Neanderthals” and “a Neanderthal” emerged in the popular literature of the 1920.” (Wikipedia. Neanderthal)
(3). Meat curing can be defined as the addition of salt to meat for the purpose of preservation. (Hui, YH, et al, 2001: 505)
(4) It turns out that “food-grade salt of the highest purity should be used in meat curing practices. Impurities such as metals (copper, iron, and chromium) found in natural salt beds, salt produced from salt springs or sea salt accelerate the development of lipid oxidation and concomitant rancidity in cured meats. Although salt may be of very high purity, it nonetheless contributes to meat lipid oxidation. Nitrite and phosphates, help retard this effect.” (Hui, YH, Wai-Kit Nip, Rogers, R. 2001: 492)
Davy, H. 1840. The Collected Works of Sir Humphry Davy …: Elements of chemical philosophy. Smith, Elder & Co.
Gouverneur Emerson . 1858. The American Farmer’s Encyclopedia. A O Moore.
Hui, YH, Wai-Kit Nip, Rogers, R. 2001. Meat Science and Applications. Marcel Dekker, Inc.
Krebs, RE. 2006. The History and Use of Earths Chemical Elements. Greenwood Press.
Laszlo, P. 1998. Salt, Grain of Life. Columbia University Press.
Pearson, AM, et al. 1997. Healthy Production and Processing of Meat, Poultry and Fish Products, Volume 11. Chapman & Hall
Rahman, SM. 2007. Handbook of Food Preservation. Second edition. CRC Press.
Figure 1: http://www.livingstoneonline.ucl.ac.uk/biog/dl/bio.html
Figure 2: http://www.france24.com/en/20121031-bulgaria-oldest-prehistoric-town-discovered-europe-provadia-solnitsata-ancient-salt-site-archaeology/
Figure 3: http://www.culturaitalia.it/opencms/museid/article.jsp?language=en&article=/en/contenuti/percorsi/percorso197/capitolo_0004.html&tematica=&selected=
Figure 4: http://www.engineerswalk.co.uk/hd_walk.html