The Stories of Salt

The Stories of Salt
By Eben van Tonder
17 July 2019

Chapter 10 of my series, The Salt Bridge

My journey of discovery of the use of salt in southern Africa brought me to Johannesburg. Minette and I wanted to be in New Zealand but dubious former business partners had other ideas.  The Universe used the bad intentions of my previous compatriots and predestined me to be in Johannesburg.  I went hiking around the country to find the soul of this land.  Suddenly, quite unexpectedly, out of the bush appeared three tribes.  One of these tribes, in particular, took me in and started showing me amazing things.  Salt itself started talking to me and took my journey further.

I scarcely landed in Johannesburg when I did the 14km hike at the Suirkerbosrand reserve just outside Heidelberg.  I completely missed the many old stone ruins.  Back home I read up on the site and discovered that a huge Twana settlement was located there.  I was back the next weekend and then I found the ancient village!

Massive South Tswana Village at Suikerbosrand (Heidelberg, Gauteng)


I saw the ruins of an impressive Tswana mega-city close to the modern-day town of Heidelberg.   At Suikerbosrand there is an ancient Tswana city. It turns out that roughly built stone structures can be seen in several locations throughout the reserve.  Over the next weeks, as I kept returning to the site, I came across many more structures.  Archeologists discovered pottery designs and other objects such as copper ornaments, iron spears, iron rods, and hoes, which identifies the inhabitants as Sotho-Tswana. The such South-Tswana settlements were present throughout Gauteng.

Judging by the dated architectural styles that were common at Suikerbosrand, it’s estimated that the builders of the stone-walled structures occupied this area from the fifteenth century AD until the second half of the 1800s.  The biggest cluster of circles on the reserve form part of a much larger settlement, with what appears to be a royal kraal with commanding views of the surrounding area.

Using recent laser technology (LiDAR), researchers were able to recreate the remains of the city. The evidence gathered by researchers from WITS university suggests that the area was certainly large enough to be called a city measuring nearly 10km (6.2 miles) long and about 2km wide.”

Here is a reconstruction of what it may have looked like, built from the results from the LiDAR research.


Parys on the Vaal and the farm of Berakah Eco Trails

Since I am close to Parys, I thought there may be great hiking trails.  Johannesburg itself is notoriously scarce in its offering to outdoor enthusiasts!  I drove to the Northen Free State town of Parys to try a new area.  I googled “hiking trails” in the area while sitting at a coffee shop in Parys and I could find only one, on the farm where Berakah Eco trails is located.  No sooner did I start the hike when I came upon another massive settlement.  By this time, I have come across a huge Twana site in Suikerbosrand and now, completely unexpected, the ruins on the Berakah farm on the Vaal River.


The Tswaing Salt Lake in Soshanguve, north of Pretoria

I was looking for a transition to enter the Gauteng region in the book I am writing on the history of meat curing.   I wanted to link my time in the story riding transport between Johannesburg and Cape Town to my quest for the origins and use of salt in southern Africa.  I was looking for possible locations where bicarbonate of soda naturally occurs which I thought would do the trick very nicely as a transition salt into my much detailed look at sodium nitrate and nitrite, ammonium chloride and sodium chloride in “Bacon and the Art of Living”.  To my great surprise, I found that high levels of bicarbonate of soda occur abundantly in Tswaing salt lake, 40km north of Pretoria.  The site is, at the same time, one of a handful of impact craters in southern Africa.

Here I discovered more ancient ruins at the impact crater which was in all likelihood connected through trade to the communities in the Suikerbosrand, the communities along the Vaal River and definitely connected to the people who lived in the Magaliesburg region.


Twana Ruins on Eastwick

As I was discovering the Tsana cities at Suikerbosrand and the sites close to Parys on the banks of the Vaal River, their important salt source of Tswaing; while salt was leading to the local tribes, I discovered the Magaliesberg sites.  This region was introduced to me by Etienne Lotter who has his farm, Eastwick Stud Farm, here where they have one of the best Nguni herds on earth.  Soon after my hikes in Heidelberg, along the Vaal River and north of Pretoria, I visited Thys and his wife on the farm and hiked to the top of the cliffs of the Magaliesberg mountains up a gorge on Eastwick. At the top, we discovered the old ruins of a large indigenous village.










The Magaliesburg mountain

The Magic of Salt

I was intrigued!  The complexity of the societies, their close interconnectedness – their size and sophistication, it all blew me away!  I realized that my quest for understanding the use of salt in southern Africa is nothing less than hearing their stories, told to me by the elders of the different villages, while we sit at the evening village fire, and eat their sumptuous dishes.

Salt is the medium that can not be understood without understanding the people who enjoyed it!  I had to learn about the people so that I can understand what salt is telling me.  THAT is my first lesson.

What will follow are the stories of salt, and we begin with the story of three tribes!



The impact of Sodium Bicarbonate and the Twaing Impact Crater

The impact of Sodium Bicarbonate and the Twaing Impact Crater
By Eben van Tonder
26 June 2019



There are many ancient salts on earth. Over the years of studying many of them, I discovered a unique and fundamental property. They are alive, able to speak, reason and will!

They direct me in my everyday work at the deli meat producer in Johannesburg, Van Wyngaardt. They commune with me at night when I sleep. They do not let me rest, directing my thoughts and inquiries. The spirit of ammonia, spirit of saltpeter, spirit of sal ammoniac, spirit of soda ash, spirit of soda; these collectively form the Spiritus Mundi, literally, the World Spirit, which, in the interpretation of Yeates, contains the collective soul of the universe, the repository of the memories of all time.

Salt and the peoples of Southern Africa

Crosscurrents converged. For years I have been studying salt from the perspective of the people of Southern Africa. I took some time during two long visits to New Zealand to study the ancient salt production in that country and expanded it to Polynesia and touching on Taiwan and China to gain a better understanding of the regional technology related to salt. I became convinced that even if there was no actual salt production in pre-colonial New Zealand, that this does not mean that the Maori did not have a sophisticated knowledge of salt, as did the people from the region it finds itself in.

Back in South Africa, I fell in love with another great African technology of cattle breading when I was introduced to the subject of the Nguni by Etienne Lotter. It is the Nguni cattle which in turn lead me to the great indigenous cultures of sub-Sahara Africa and I started seeing these people, not as primitive humans, but very sophisticated societies.

I was trying to imagine apart from sodium chloride, what salts would the peoples of southern Africa have encountered and then, more importantly, what did they use it for. The most obvious answer for me, apart from sodium chloride, was to start with bicarbonate of either sodium of calcium.

Sodium Bicarbonate

Calcium bicarbonate was a logical starting point due to the existence of so many limestone caves in Southern Africa. My own exposure to caves taught me that stalactites and stalagmites form in limestone caves. Limestone contains at least 50% of calcium carbonate which dissolves in water. The water, in turn, contains carbon dioxide. Calcium bicarbonate is formed and the reaction is represented as follows:

calcium carbonate in water with carbon dioxide

The water with the calcium bicarbonate travels through the ground to the roof of the cavern where it comes into contact with air and a reaction takes place that creates calcium carbonate again which is deposited on the cave floor or suspended from the ceiling forming either stalagmites and stalactites. The reverse reaction where the calcium carbonate is created is represented as follows:

calcium bicarbonate to calcium carbonate.png

We are familiar with the effects of calcium bicarbonate in hard water where buildup is caused in one’s bathroom or kitchen and is difficult to clean. In limestone caves, the white calcium buildup is seen everywhere and these would have been tested by the industrious Africans. The custodians of chemical technology in Africa, as in probably all parts of the globe, was at some point the domain of the Sharma and healers. The white precipitate in the caves would have been heated, burned, rubbed onto wounds, tasted, used in foods, in water, in drinks and part of various potions and purely based on observation and by elimination, the properties of the salt would have been elucidated.

Calcium carbonate and calcium bicarbonate in terms of food preparations and preservation would not have done much. The only place on earth where I could find calcium carbonate or bicarbonate being used in food preparations is in Korea. Sodium bicarbonate, however, is a completely different story. I knew this from my work on another great African salt, Natron.


Natron contains around 17% sodium bicarbonate (NaHCO3). The other chemical present is sodium carbonate decahydrate (Na2CO3·10H2O, a kind of soda ash) and a small quantity of sodium chloride and sodium sulfate. I was first alerted to the preserving power of Natron when I realised its role in embalming. (Salt – 7000 years of meat curing) It is not hard to guess the extreme effective nature of sodium bicarbonate in preservation.

Corral, Laurie, Thomas, and Montville (1988) published a key paper on the use of sodium bicarbonate in meat preservation, Antimicrobial Activity of Sodium Bicarbonate.

I, myself, started using it with tremendous effect as a meat preservative. I wondered if there is any place in Southern Africa where sodium bicarbonate naturally occurs.


Twaing Impact Crater

Of course, it occurred naturally wherever Natron was found, but what about Southern Africa? To my great surprise, one of the very few places sodium bicarbonate naturally occurs is at a very special site, 40km’s North of Pretoria called Twaing. It means “the place where salt is.”

Around 220 000 there was an event where a meteorite struck the earth at this site. It exploded and vaporized on impact and the impact craters and the salt lake was formed.  The small groups started visiting Twaing between 130 000 and 30 000 years ago after the plant life was restored and animals returned to the region following the impact event. These groups came here to hunt, gather plant to eat and use for medicine and, of course, to collect salt. They made stone age tools and weapons. Scrapers, points and stone tools that were thrown away were found at Twaing. None of the rocks at Tswaing is suitable for making such tools and points, showing that these objects were brought from somewhere else. Interestingly enough, there were also artifacts found at Twaing that is smaller than the ones from the Middle Stone Age which we just referred to. This may indicate that the ancestors of the San Bushman who lived from 30 000 to 2000 years ago visited the site during a time known as the Late Stone Age.

The first ancestors of the current indigenous people, the first farmers to use iron age tools, migrated to South Africa 1850 years ago. The first Iron age people came to Twaing around 800 and 900 years ago. Decorated clay pot fragments found on the crater floor shows that these people were Sotho or Tswana speaking communities known as the Miloko who used the salt to preserve and flavour food and trade with it. It shows that by and large, people did not stay very long at Tswaing. It seems that most people who came to the crater was periodic visitors from the Waterberg area (and other locations). So far they have only found one Iron Age community at Tswaing along with a grindstone, decorated and undecorated potsherds.

There is evidence that the salt they collected was used for flavouring, food preservation, and trading. A large number of undecorated potsherds found in the crater indicate shows that Tswana and Sotho speaking people made up most of the visitors until the advent of the time of the Matabele in the 1820’s.

In the 19th century, factors such as drought, famine, competition for grazing, wood, and water and trading routes precipitated tremendous unrest and conflict between the Iron Age Inhabitants of South Africa. New political groupings were formed and new kingdoms emerged and militarism grew.

One such empire was the Ndebele (Matebele) empire. They established themselves north of the Vaal River in the early 1820’s. A band of Nguni refugees under Mziklikazi from KwaZulu-Natal started attacking and defeating Sotho tribes. In 1827, the kingdom relocated to the Magaliesburg region. From there they launched attacked and conquering Tswana/ Sotho chiefdoms to the North and West. It has not been proven, but it is very possible that the Matebele visited Twaing to collect salt and hunt the many wild animals who congregated there.

For most of the 19th Century, Tswaing remained the key salt lick north of Pretoria. Large herds of game gathered here including elephants until the early mechanized salt mining operation scared them away.

Tswaing: Sodium Bicarbonate and an Impact Crater – a massive impact

On Saturday, 22 June I visited the Tswaing impact crater and salt lake. I set off with a guide on the roughly 7km hike on the crater rim. In the first video, I arrive at the salt lake and impact crater.

Arriving at the water’s edge. The boreholes were drilled as a means to extract the salt brine. The taste of the salt is amazing! It has a depth in taste that surprises you! It is less salty than one expects and the aftertaste is exquisite!

Sampling the salt and the background of the salt.

What was it like arriving at the site 200 years ago?

Running towards the water’s edge.

Taking water samples and thinking about life.

Photos from the impact crater.


The impact of the crater has been profound. The knowledge of the ancients was impressive and their technology sophisticated. Sharing the space and knowledge possessed by the ancients is one of the highest privileges on earth! It was fantastic being here and continuing to understand the implications of this site.


All information about Twaing, from the official documentation and resources at the site.

Arnay-de-la-Rosa, M., González-Reimers, E., Pou-Hernández, S., Marrero-Salas, E., and García-Avila, C.. 2017. Prehispanic (Guanches) mummies and natrium salts in buria caves of Las Cañadas del Teide (Tenerife). E. Schweizerbart’sche Verlagsbuchhandlung, 70176 Stuttgart, Germany
DOI: 10.1127/anthranz/2017/0662.

Project – Legendary Foods

8 June 2019
Project Legendary Foods
Eben van Tonder


I moved to Jhb for work three months ago.  I joined a very special company called Van Wyngaardt.  The mission of the company is very simple, to create legendary foods and our pay-off line, created by Etienne, is “Exceedingly Good Meat.”

A massive Tswana City on Suikerbosrand

Last weekend I did a 12km hike at the Suikerbosrand Nature reserve 60km outside Johannesburg, past Heidelberg on the way to Durban.  I was browsing the web for interesting information on the area and learned of a massive Tswana city which was located here. I made contact with Talfrein Harris whos friend, Stephen Banhegyi, worked on the site for his master’s thesis.  They could not take me out to the site this weekend, but I was back early this morning to see what I can find.

As I hiked up a path this morning, I suddenly realized that I was on the edge of many of the stone structures.

From my reading on the web, I learned that the city was massive!  10km long and 2km wide. By comparison, Mesopotamia was only 2km in diameter. Friday evenings I am watching on Discovery how new technology, called Lidar is used to see through the vegetation using laser lights which helps researchers to recreate the world of the Maya civilization.     The exact same technology is being used at the site on the Suikerbosrand.

There were many large Tswane cities scattered along the northern parts of South Africa until the 1820’s when they collapsed in the Difeqane Civil wars.  Archeologists use the building style to estimate its creation around the late 1400’s AD the city is believed to have been abandoned around the second half of the 1800s with between 750 and 850 homesteads in the city.

The ancient homesteads at Suikerbosrand are shown against an aerial photograph from 1961. The two rectangles show the footprint of the LiDAR imagery. Karim Sadr

As I moved up the hill and was suddenly right in the middle stone walls.  I was thrilled and the best thing about it all is that I have a little insight into how they ate their meat.  Yesterday I discovered a quote by Lichtenstein that confirms the practice of Southern African tribes who used ash as salt.  It is in reference to Tswana people in the northern Cape area and he wrote about them that “salt properly, they have none; instead of it they make use of natron, or the ash of a certain salt succulent plant: their favourite mode of dressing their meat is to roast it in the ashes.” (Lichtenstein, 1803)  We will return to his reference to natron which certainly does not refer to natron from the Natron valley in Egypt.  The primary interest is his reference to salt from ash. I have been researching salt and the ancient people of South Africa for years and I know how they cooked their meat! My intention is to recreate it as closely as possible.

In Johannesburg, I joined the only company in South Africa who allows me and the amazing team working with me to te recreate these legendary dishes.  The intention is not just to do that but to recreate local dished with local ingredients, inspired by the greatest fermented, cured, and smoked products.  We want to make hams and salamis and bacon according to many years of German and Italian, Spanish, Dutch, Danish and English traditions, but marry it with the richness of the South African cultures and we want to incorporate into it, the arts of cooking from Africa!  Besides processed meat, we want to celebrate great South African cattle breeds by making traditional Afrikaans and South African dishes from the best meat created by many years of evolution and careful breeding, right here in our own land.

The section I am starting today is intended to house our research projects and feature our best creations.  There will be old favourates like biltong, droe wors, bacon, and salami, but this will only be the start.  We intend creating legendary hams and other cured and fermented products with local flavours and using our local climate to do most of the work.

Legendary!  Insanely legendary!

Photos from the cite.  The first and last photos are recreations from the Lidar project.

Further reading

Artisan Curing and Traditional Meat Dishes


Mild Cured Bacon – Recreating a Legend


Irish Mild Cured Bacon was invented by Mr. William Oake of Ulster sometime in the late 1820s/ early 1830s. Mild cured bacon was the first technical development away from traditional dry cured bacon that was practiced for millennia. It was replaced by the modern high injected, industrial bacon following World War 1. The use of needles to inject brine into the meat tissues was incorporated into the system very early on. Needle injection itself was invented in c. 1850, also in Ireland.

Original Method

Brine was prepared and sterilised. Meat was soaked in liquid brine for 7 days. After brine soaking, it was rested for up to three weeks and smoked. Smoking was done for between 24 and 48 hours.

The simple brine make-up was:

10 lb salt (54%)
8 lb of dark brown sugar (43%)
1/2 lb of saltpeter (2.7%)
Total brine: 18 1/2 lb. (100%)
Dilute it in water, but it must be able to float an egg.

Recreating a legend

In 2019, I joined a unique company in Johannesburg. They gave me the opportunity to recreate Mild Cured Bacon and we are making it available to a carefully selection of retail outlets and catering clients.

Product Features

Irish Mild Cured bacon is an excellent example of traditional methods, natural ingredients and a pure meat product, unadulterated by modern influences.

Recreating a Legend

The first step was very successfully tested wit the expert help of Carlo and Stephen at Van Wyngaardt on 16, 17 and 18 May 2019. The four week period was reduced to three days for testing purposes but the process steps were retained. The results were spectacular.

The brine composition was retained with the exception of the salt and saltpeter quantily which is reduced to much lower levels. Sugar levels are also reduced to prevent burning in the pan due to excessive caramelisation. Ascorbate, a natural product, is added to comply with legislative requirements.

The next phase is to adjust the time closer to the original. As it is, what we created is EXCEEDINGLY good meat!

Superior in Every Way

Newspapers started tracking the price of Mild Cured Bacon from 1842. It shows the place it occupied as superior to any other system and its legendary status. Mild Curing was finally abandoned after the First World War when it was replaced by quick curing, high volume, high injection modern bacon processing methods. It is safe to say that following the war, apart from small artisan operations, it, by and large, disappeared until our recreation!

Here are a few quotes about it followed by the actual article or advertisement.

Mild Cured Irish Hams and Bacon – “The best ever sold”

Milde Cured Bacon AdvertThu, Jan 13, 1910 – 4 · Butler Citizen (Butler, Pennsylvania) ·

Widely advertised and “Mild Cure” used as the key product feature.

Sat, Oct 2, 1886 – 4 · The Freeman’s Journal (Dublin, Dublin, Ireland) ·

Often repeated – adverts like this appeared countless times.

Tue, Jan 4, 1910 – 7 · Butler Citizen (Butler, Pennsylvania) ·

Mild Cured Bacon – “Greatly praised by purchasers”.

Mon, Aug 30, 1886 – 4 · The Freeman’s Journal (Dublin, Dublin, Ireland) ·

Mild Cured Bacon – “met by good sales.” In comparison, “scarcely any business has been done” in competing, “inferior” products.

Wed, Oct 14, 1846 – 4 · The Weekly Standard and Express (Blackburn, Lancashire, England) ·

“Choice Mild Cured Bacon”.

Sat, Mar 9, 1844 – 8 · The Hampshire Advertiser (Southampton, Hampshire, England) ·

“Brisk demand” for “mild cured meat”.

Fri, Jun 23, 1843 – 4 · Belfast News-Letter (Belfast, Antrim, Northern Ireland) ·

“Bacon market dull .., except for choice. . . mild cured bacon“.

Fri, May 27, 1842 – 4 · Belfast News-Letter (Belfast, Antrim, Northern Ireland) ·

“Bacon market flat, . . . but “mild cured is much sought after.”

Fri, Aug 19, 1842 – 4 · Belfast News-Letter (Belfast, Antrim, Northern Ireland) ·


The grandeur and magnitude of producing these legendary foods cannot be overstated. Being involved in the project is an honour. Modern demands of “lower prices” has chipped away at the heart of what made bacon from the late 1800s EXCEEDINGLY great! We are delivering on a vision to put EXCEEDINGLY good-ness back into meat!

Further Reading

Tank Curing Came from Ireland

Dr. Morgan’s Arterial Injection

Nguni: Living Works of Art

27 April 2019



Cattle are ancient, magical, living works of art.  Antjie Krog in her book Change of Tongue writes: “In Setswana, cattle are known as modimo o nko e metsi – god-with-the-wet-nose…. On Saturday I spent the afternoon with the kids among one of the greatest Nguni herds on earth, at Eastwick Stud Farm of Etienne Lötter, managed by Thys Koen.  I have been reading about their origins and followed their ancient migration routes into West and Southern Africa.

Here I will look at what it takes to breed great cattle but they are more than just a technical consideration. A poem is, therefore, a great first look at them.


Nguni Herds

Margaret Epstein
Translated from the Afrikaans by the poet

Nguni herds
shift silently as spirits
Across the face of the earth.

Back and back they go,
generation upon generation
through Africa’s history,
forming a bond between man and beast.
Reckoned in honour,
pride and wealth.

To reflect an eternal
forming and dissolving pattern
of shadows and sunlight,
mud, pebbles, rocks
and grains of sand.

In the silence of heat,
under thorn tree branches,
alongside pools of water and cliffs,
across centuries
the sound of bellows,
the blowing of cattle breath
and voices calling,
echo through a haze of dust.

Spoor of cattle and men
lie stretched out over plains
and mountains.
Their marked skins and graves,
eternal signs of temporary ownership,
are alone and deserted,
lost, disintegrated in the veld,

Now we stand
in this time and place,
to admire Nguni cattle, their distant past,
innocence and patience,
patterns of spots, horns, blemishes
and intimate family conversations.

Remember the old links,
but loosen the bridle
of today’s constraints.
Free your thoughts to wander with us,
to dream.


IMG-1849 (1)



Photos by © Eben, Tristan and Lauren van Tonder
Poem Nguni herds  © Margaret Epstein
From the anthology Africa! My Africa!
ISBN 978-1-874915-20-1

Further Reading – Nguni – its origins

New perspective on the origin of Nguni cattle

DNA markers reveal the complexity of livestock domestication

Domesticating Animals in Africa – Implications of Genetic and Archaeological Findings


MDM – Not all are created equal!

MDM – Not all are created equal!
By Eben van Tonder
16 April 2018



Last Saturday I turned 50.  I did three things that I insanely enjoy.  One was to spend time with a meat and business legend.  Over the years I have researched and got to know many such men.  Those who are still alive, I got to know personally.  Those who passed away, I studied their lives.  Jacobus Combrink who created arguably the most successful butchery in South Africa in the 1800s;  David de Villiers Graaff, his protege and the man who took Combrink & Co. and turned it into the Imperial Cold Storage and Supply Company Ltd. (ICS) which in turn merged into the food conglomerate Tiger Brands with the Combrink & Co part of the operation being assimilated into the Enterprise/ Renown merger;  JW Moore who set up the Eskort curing operation under his Farmers Cooperative Bacon Curing Company in Estcourt, Natal.  Further afield there is the three Harris’s.  Nick Harris, whom I have the privilege to know, was key in the creation of the New Zealand curing operation, Hellers.  Together with his brother, Bryan, they currently own an abattoir, deboning and processing plant in Cheviot where they grow up and where Nick owns large farmland.  From the previous century, the brothers George and Thomas Harris from Calne in Wiltshire who created C & T Harris, arguably the most successful bacon operation in British history.  From Australia, Wright Harris and his Castlemaine Bacon Company who fought in the second Anglo-Boer war in South Africa.  Interestingly enough, none of the Harris’s from New Zealand, Australia or England are related.  From the USA there is the legendary Philip Armour and his Armour Packing Plant in Chicago who was, according to my research, closely linked with the direct addition of nitrites in curing brines. His company is one of the reasons why anti-trust laws exist in the USA.  For my 50th birthday, I was on the farm of Etienne Lotter.

Etienne stands shoulder to shoulder with any one of these formidable men. It fascinates me that all these men share an unwavering focus, the ability to make quick and good decisions, resolve of steel, passion, commitment, and an obsession to invest in people.  A story is told of Phil Armour that he showed his packing plant to visitors one Sunday.  Ford got his idea about assembly lines from Phil and it was indeed something to behold.  A newspaper reporter tells the story that they were walking back from the factory and could see the church where many of the men who worked for him attended adult education after church.  He reportedly pointed to his packing plant and said, “there we make bacon” and then to the church and said, “and there we make men!” He liberally invested in people and he himself claimed that he never fired someone.  That is not to say that it was easy to work for him as is or was true of all these men.

The second thing I did which I insanely love was to hike up the Magaliesburg on Etienne’s farm, Eswitch Stud Farm.  There was no clear footpath up and it made for an adventure through the thick grass, trees, and ferns.



The 3rd thing was talking meat curing with Etienne the entire Saturday and Sunday morning!  The experience was volcanic with its seismic aftershocks still reverberating through my psyche!  I’ve been in the meat industry no for 14 years.  Till my day with Etienne, I thought of MDM (Mechanically Deboned Meat) as something like flour or sugar, a commodity of uniform characteristics and quality.  Was I wrong!  It turns out that as is the case with all ingredient, functionality follows processing techniques.  Inspired by Etienne’s passion for MDM, I started to investigate  What a world started opening up!  I share some of my initial discoveries.


“Mechanically deboned meat (MDM), mechanically recovered meat (MRM) or mechanically separated meat (MSM) are synonyms used to mark the material, obtained by application of mechanical force (pressure and/ or shear) to animal bones (sheep, goat, pork, beef) or poultry carcasses (chicken, duck, turkey) from which the bulk of meat has been manually removed” (Hui, 2012)

There are a number of different methods to achieve this, but most of them result in cell breakage, protein denaturation, generally an increase in lipids and haeme groups and poorer mechanical properties.  (Hui, 2012)

MDM is mainly used in producing emulsion-type products such as Vienna’s, Russians, and Polony (in South Africa).  “Meat recovered from bones or carcass parts by mechanical procedures is generally considered to be of poor nutritional and microbiological quality”  (Hui, 2012)  In many parts of the world, strict legislation governs the use of these products.  When compared to the rest of the world, South Africa lags behind in this regard.  There are certain producers who choose to only use muscle meat in the production of its emulsion sausages, loaves, and hams, and the consumer is entirely left to study ingredients declarations to determine if MDM is present or not.  There are also a number of different qualities of MDM and it is by no means correct to claim that all MDM are of poor microbiological quality and share the same low nutritional characteristics.  The different production methods of MDM can broadly be separated into hard and soft MDM.

Hard MDM

Hard MDM is made from pork or beef where it will be hard to clear the bones from all the small meat bits.  When the valuable pieces of chicken and turkey (wings, breasts, and legs) are removed, hard MDM is made from the carcass that is left.  In this method, the bones or carcass is placed in some kind of a pressure chamber with small holes in it and the bones or carcasses where are subjected to high pressure which removes the skin, meat bits, connective tissue, etc. still stock to the bones.  These pass through the small holes of the barrel sieve (around 0.5 – 0.8mm in diameter).  The basic principle remains the same across many different machines namely that high pressure is used to clean the bones.  (Feiner, 2006)

Hard MDM should not contain bone bits larger than the hole size of the sieve, but in reality, on account of the enormous pressure used to remove the fragments from the bones, they often do.  The consequences of the presence of bone pieces in the MDM elevates the calcium and phosphorus content in hards MDM quite high.  These, in turn, interferes with the functionality of phosphates in emulsion sausages.  (Feiner, 2006)

The micro status of hard MDM is of great importance.  The reason for the high micro in this MDM is the large surface area of the meat.  The levels should not be higher than normal minced meat.  As always, processing conditions play the key role here and low micro levels are never guaranteed. (Feiner, 2006)

Another problematic feature of hard MDM is the presence of bone marrow, particularly in chicken MDM.  This speeds up the oxidation of fat since bone marrow contains a fair amount of metals such as iron, magnesium, and copper “which acts in a pro-oxidative manner.” (Feiner, 2006)

The fat content of hard MDM is inconsistent.  Protein, fat and bacterial levels should be part of MDM specifications.  The shelf life of pork and chicken MDM is much shorter than beef MDM in both chilled and frozen state.  The reason is the fatty acids in pork and chicken have high levels of unsaturated fatty acids in the fat fractions when compared with beef.  “Rancidity develops quickly within such material.”  (Feiner, 2006)

MDM has a  pasty texture. Due to the meat recovery method, there is a high proportion of “pulverised muscle fiber residue.”  There is also a large proportion of “partly destructured muscle fibers.”  We call such change in muscle fiber ‘‘destructuration” (Sifre and others 2009)”  (Feiner, 2006)

Soft MDM

Soft MDM, on the other hand, is produced from meat trimmings, high in connective tissues.  The process avoids the enormous pressure of the hard MDM methods by the action of a roller on the meat.  In this system, the material is put through a machine that separates the meat from connective tissues, cartridge, etc. based on the different hardness of these components.  The process is much more productive in terms of time and input required when compared to the hard MDM methods.  In many instances, a “Baader” machine is used or something similar. (Feiner, 2006)

A very typical production method is as follows.

  1.  Grind minced meat through 13 – 20mm mincer plate;
  2.  Feed through Baader machine
  3. The Baader machine has small holes in a rotating drum and the meat passes under the drum so that the drum presses ON the meat.  The soft lean meat, due to its texture, passes through the holes in the rotating drum and is collected there and fed out on the side of the machine;
  4. The harder connective tissue, bone fragments, etc. are ejected at the front of the machine, having been unable to be pass to the inside of the drum where only soft lean meat is collected. (Feiner, 2006)

Both the collected connective tissues, sinews, etc and the soft MDM from inside the drum has enormous functional applications and products are made from both.

Comparing hard MDM and soft MDM, the following functional differences emerge:

Soft MDM Hard MDM
Protein Content:  15% – 17% Protein Content:  12% to 15%
Of this, 70% to 80% is equal to protein found in muscle meat. Of this, 60% to 70% is equal to the protein found in muscle meat.
Consequently: Consequently:
– Much improved WBC (Water Binding Capacity); – Reduced ability to immobilise water
– Much improved ability to emulsify fat – Reduced ability to immobilise emulsify fat
70% to 80% WBC and emulsifying characteristics of lean muscle meat
All protein in soft MDM still functional Reason is: denaturing of proteins and cell breakage during processing.
Fine and mushy consistency
– Do not support firmness in final product
pH: between 6.2 and 6.4
– poor colour developmenty
– MDM only products exhibit a darker colour.


Examples of legislation in place in many parts of the world related to MDM are the following:

Bones to be used in the production of Hard MDM must be stored at between 0 and 2 deg C no longer than 24 hours or be frozen for a maximum of 8 days before it is processed.  If it is frozen, this must take place immediately after production.  The chilled bones must be utilized within 24 hours.

Besides these, fat percentages, minimum requirements on nutritional value, and percentage connective tissue are set in many countries.

Functional Characteristics

Despite the fact that many different MDM producers achieve these values, there exists an enormous range of varying functional characteristics of MDM, produced by different manufacturers, on account of different process and machines employed in its production.

Lets first evaluate meat that was recovered through deboning with meat processed with an MDM machine. Froning (1970) for example compared hard deboned white and dark chicken meat with chicken backs and necks and turkey frames processed with a Paoli machine and chicken backs processed with a Beehive deboner for emulsification properties. (McMillan, 1980)

He found that MDM was most stable in a bowl cutter to temperatures of 7.2 to 12.8 deg C. Above 12.8 deg C, the tensile strengths of finished emulsions decreased and the amounts of fat and gel-water released during processing increased. By comparison, the hand boned broiler meat was stable at all chopping temperatures.  (McMillan, 1980)

He further found that MDM had less protein matrix available for emulsion than hand-deboned meat, “due to greater collagen dispersion and possible loss of protein solubility caused by deboner protein denaturation.”  (McMillan, 1980)

The tests may have been conducted in the 1970s and 1980s, but the principals are equally valid.  Froning  et al. (1971) used 15% turkey MDM in red meat frankfurters to study its stability and acceptability. The MDM was produced with a Paoli deboning machine and the results indicated a higher capacity to emulsify oil per 2.5g sample than pork trimmings, but a reduced capacity than boneless cow meat.  (McMillan, 1980)

Turkey MDM  had a reduced WHC compared to red meat sources.  Gel-water loss was greater in frankfurters made with 15 percent turkey MDM.  Their research alluded me to another very important consideration in the functionality of MDM.  In SA, all MDM is sold frozen, but in other countries, MDM is customarily produced, sold and used unfrozen.  Froning  et al. found that frankfurters which fresh MDTM had less cook
than franks containing MDTM which was stored frozen for seven days prior to use.  (McMillan, 1980)

In terms of taste, no major differences were found between control frankfurters, frankfurters containing previously frozen turkey MDM and fresh MDM in terms of taste and colour.  The superiority of pure meat over MDM was confirmed by Schnell et al (1973).  They compared poultry MDM with hand boned carcass meat.  The texture frankfurters produced with hand-deboned meat was firmer than those produced with MDM. (McMillan, 1980)

Another interesting study, confirm the differences between different MDM producers was done by Baker et al. (1974).  They compared poultry MDM from three machines to measure the effect of chopping time on taste panel evaluation and frankfurter stability. “Chopping time had little effect on results of these tests, but source of the MDPM caused differences in frankfurter yield, stability during cooking, emulsion viscosity, and taste panel scores of texture and juiciness. More dense poultry MDM and smaller, more evenly distributed fat globules contributed to the stability of frankfurters with two of the poultry MDM sources as compared to the third MDPM source (Angel et al., 1974).  (McMillan, 1980)

Some researchers have reported that they were able to “manage” negative characteristics in certain MDM typed through various techniques such as controlling and altering the pH, but if this can be duplicated in a factory environment if questionable.

Foodnavigator reported in 2018 on a project in the EU seeking to test MDM in terms of the structural integrity as a key indicator for its quality. The software reportedly use image processing algorithms to quantify degrees of degradation in meat. The aim is to test cheap imports into the EU which claims comparability with high quality EU MDM.

In the EU, certain producers such as Polskamp Meat Industrie in Holland is able to produce MDM of exact specifications. Processors can choose fat content of ±11%, ±12%, ±14% and ±16% and protein content of between ±15% to ±18% The colour of their chicken MDM is consistent being the typical colour of fresh chicken meat of pink-red. This sets them apart from many producers who is unable to certify such exact parameters, again confirming our thesis that not all MDM are created equal!

Polskamp is a good example of using technology to overcome the inherent problems in hard MDM. They pioneered low pressure technology to remove meat from bones, thereby avoiding the negative aspects associated with high pressure meat separation.

They claim that their 3 millimeter meat is “produced using special machines that can separate meat from the bone. Contrary to mechanically separated meat, 3 millimeter meat is produced using low-pressure technology that better preserves the structure of the chicken meat. 3 Millimeter meat is also characterised by its lower calcium content and lighter colour. Polskamp Meat Industrie offers its buyers several types of 3 millimeter meat, e.g. a white product and a rose-coloured product.” (


These and more recent studies indicate the need for the processor to conduct a thorough evaluation of its MDM source.  At the end of the day, all these studies point to the fact that the different MDM’s on the market, produced by various manufacturers, using a range of different source material’s are not all created equal.

By choosing the right MDM source, it may be possible to omit binding and water absorption material such as the different soya products or starches.  The effect of freezing and freezing time on MDM is another key aspect to be evaluated and along with aspects such as fat %, connective tissue%, and water content must command our careful attention.

Finally, careful attention should be given to the different methods to extend the shelf life of MDM by reducing lipid peroxidation and of microbial growth.

Even if pure meat products is our objective, the lessons found in the production of MDM and the subtle techniques of optimizing yield, profitability while achieving exceptional product quality will benefit us tremendously if we master it!

Further Reading

The nutritional and physical characteristics of mechanically proc

Hui, Y. H. (Editor) 2012. Handbook of Meat and Meat Processing. CRC Press.

Hiking photos

It is not every day that one turns 50.  Here are the rest of the photos from my hike up the Magaliesberg on 13 April 2019.

Hiking Photos – 50th birthday


Feiner, G.  2006.  Meat Products Handbook: Practical Science and Technology.  Woodhead Publishing.

Hui, Y. H. (Ed.) 2012.  Handbook of Meat and Meat Processing. Chapter: Mechanical Deboning.  CRC Press; Taylor & Francis Inc.

McMillan, K. W..  1980.  The nutritional and physical characteristics of mechanically processed beef and pork product.  Iowa State University.  Retrospective Theses and Dissertations. 7342.

Photo Credit:

Continental Franks:

All other photos by Eben

Chapter 7.03 Dr. Polenski


The quest to understand how great bacon is made takes me around the world and through epic adventures. I tell the story by changing the setting from the 2000s to the late 1800s when much of the technology behind bacon curing was unraveled. I weave into the mix beautiful stories of Cape Town and use mostly my family as the other characters besides me and Oscar and Uncle Jeppe from Denmark, a good friend and someone to whom I owe much gratitude! A man who knows bacon! Most other characters have a real basis in history and I describe actual events and personal experiences set in a different historical context.

The cast I use to mold the story into is letters I wrote home during my travels.

Dr. Polenski

April 1891

My dear Son,

The Noord Nieuwland in Table Bay 1762

Since my last letter about the city and the food, the strange shops, elevated above the streets, the beer and the warm people, I realised that the culture of this amazing land is having just as big an impact on me as what I am learning about the curing of bacon.  I wrote Minette two letters in which I laid out how unbelievable it is that I came to this land first who adopted the Irish system of curing and took it to new heights by combining it with their powerful and unique cooperative model!  Andreas gave me a word of caution that knowing the steps of a process and understanding the process are two different things. No sooner did I hear those words when the ever-resourceful Jeppe presented me with the next gold nugget.

After supper, at the Østergaard home, we follow another tradition of this knowledge hungry people and read together and discuss what was read.  This is customary in many households. The Danes have a  practicalness about them.  As I have seen from their unique high school model, they never stop learning and if something works, they adopt it.

Every night after supper, Andreas’ dad reads for us from a book called Foods, written over 20 years ago in the 1870s by an Englishman, Edward Smith.  He helped me to see the curing of meat as both a necessity and a delicacy.  We cure meats because, for the most part, using modern curing methods, cured meat tastes great.  On the other hand, meat curing was started to impart longevity;  to prevent spoilage.

Back home we are of course well familiar with the value of meat that “last.”  In Europe and England with their growing populations and vast navies which have to be fed, it has been an obsession and a priority to solve the problem of conserving meat for future use.  Edward Smith says in his book that “the art of preserving meat for future use, with a view to increase the supply and lessen the cost of this necessary food (meat), is of very great importance to [England] and all the available resources of science are now engaged in it.” (Smith, 1876: 22)

He lists the main ways that this is being done as “by drying, by cold, by immersion in antiseptic gasses and liquids, by coating with fat or gelatin, by heat, salted meat and by pressure.” (Smith, 1876: 22 – 38)  All have their benefits and disadvantages and I have a feeling that over the years, the technology within any one of these groups may develop, but these broad categories will remain and continue to be available to the public.

Edward Smith says that pork is particularly prized over beef and mutton because of the  “taste, but chiefly perhaps [due] to the universal habit among the peasantry of feeding pigs, which has descended from Saxon times.  Moreover, there is a convenience in the use of it, which does not exist with regard to beef and mutton, for in such localities the pork is always pickled and kept ready for use without the trouble of going to the butcher, or when money could not be spared for the purchase of meat.”  Pigs proved to be an equally prized meat in the new world due to the “ease with which pigs are bred and reared, and the meat preserved, whilst there is great difficulty in obtaining a sufficient number of persons, in a thinly populated country or a small village, to eat a sheep or ox whilst meat is fresh.  (Smith, 1876: 59)

“Bacon is made when cuts from the pig are preserved by salt and saltpeter.”  (Smith, 1876: 64).  This gives bacon its characteristic pinkish/ reddish colour, a nice flavour, and it lasts a long time before it tastes “off”.  This is the kind of things we learn at night.  After a good supper, we discuss what has been read for an hour or two before retiring to bed.

In the day I work at Uncle Jeppe’s cooperative bacon curing factory.  I started working in the curing and spice department where we mix herbs and spices.  Uncle Jeppe is a knowledgeable man and it seems as if he has been around in the meat industry forever.  I have not asked him any question that he did not know the answer to.

Take saltpeter for example. It is the curing salt for bacon which I work with every day in the curing department.  When we do dry curing, we use 1.25 st. (10 pounds) salt, 0.375 st. (3 pounds) of brown sugar, 0.04 st. (6 ounces) of black pepper and 0.02 st. (3 ounces) of saltpeter.  We use 1.25 st. (10 pounds) of this mixture per 12.5 st. (100 pounds) of meat.  (1, 2, 3)  The Irish system of mild cured bacon calls for a liberal use of saltpeter and the purer form of sal prunella. This is the main curing system we use and in both dry curing and tank curing (as mild cure is also called), it is a key ingredient.

What confused me much about saltpeter was that Trudie’s dad, Anton, also talks about the value of phosphates and saltpeter in fertilizing their fields in the Transvaal.  I have learned in school that saltpeter is one of the ingredients in gunpowder.  I know that the Dutch East Indian Company was created, in part, for the purpose of transporting saltpeter from India to Amsterdam and other European cities like Copenhagen for fertilizer and to make gunpowder. I always wondered if it is the same substance that is used to cure meat and if it is, how can this one substance be useful for such diverse applications.

I asked Jeppe about saltpeter one morning.  He put his arm around my shoulders and told me that there are interesting answers to these interesting questions.  That he hopes I paid attention in chemistry class in school.  For the next week, our Tuesday and Thursday afternoon classes during lunch break were dedicated to saltpeter.

The power of saltpeter is the fact that it contains nitrogen and nitrogen is one of only two elements, with carbon, that can exist in 8 oxidation states.  This means that nitrogen can react in a diverse and complex way and, like carbon, is foundational to all of life.  The two substances that contain nitrogen, most familiar to us, are saltpeter and ammonia.

The nitrogen in saltpeter and ammonia makes it very reactive, giving it an explosive power.  In saltpeter it has a particular effect on blood, explaining the fact that it gives cured meat its pinkish/ reddish colour.  Nitrogen exists in the first place as a gas in our atmosphere and comes into our world in different ways, the most important being through microorganisms with the ability to take it from the air and convert it to food for plants.  The plants take these compounds from the soil and water where the bacteria lives and nitrogen become part of the plant’s structure.  This is why saltpeter is a great fertilizer.  It is plant food!

Uncle Jeppe will tell me the fascinating story of how this was discovered but he said I had to be patient to hear this another day.  I am here to learn the modern way of curing bacon.  In Europe, I find myself right in the middle of the most up to date and advanced thinking about curing.

I know the steps and benefits of the Irish system, but science is only now unlocking the “why?” and “how?” behind its power. A major step has been taken in understanding the speed and better consistency in mild curing when compared with dry curing when a friend of Uncle Jeppe discovered something remarkable.

His friend’s name is Dr. Ed (Eduard) Polenske (4), a chemist, working at the Imperial Health Office in Germany.  Jeppe tells me that 1891 will forever be remembered as a watershed year for Woody’s since it is the year I arrived in Denmark and started learning about bacon curing; for the curing industry in South Africa since it is the year when Woody’s took the first steps to excellent bacon in Africa; and for the curing industry around the world because of Ed’s discovery.

It is the year when he made a startling discovery that brine and cured meat contain nitrite. This is remarkable since we know that saltpeter does not contain nitrite, but nitrates and we only use saltpeter in curing of meat which begs the question as to where the nitrite comes from.  Even though nitrite and nitrate are spelled almost the same, in reality, these are two completely different compounds with different characteristics.  Despite the fact that we do not add nitrite to the meat, how does it get there?  It is also a fact of great concern because nitrite is very toxic.

So, before Uncle Jeppe learned about Dr Ed’s findings in 1891, what we knew is that only saltpeter or nitrate is used to cure meat.  We also know that the Irish system of curing compared to dry curing cures the meat much faster.  This matter of the speed of curing is important.  Dry curing is accomplished in 28 days where mild cured bacon can be produced in 19 days. On farms, long curing is generally not a problem, but for a commercial curing operation, it means that you keep large stocks of bacon that are in the process of curing. If you produce bacon for household consumption, that is one thing, but when you have an army to feed, speed is of the essence.  Speed to the modern curer is key.

Jeppe and Ed met up in Wiesbaden, Germany, earlier this year.  This has been an annual winter ritual when the two men took their annual retreats at the same time.   They became acquainted at the  General Congress on Hygiene in Brussels in 1852.  It is exactly the hygienists that Dr. Ed fears will be most concerned about the fact that he found nitrites in cured meat.

Both men attended the conference and struck up a friendship based on their shared passion for good quality and safe meat.  Wiesbaden is famous for it’s hot springs since ancient Roman times and the second shared love between these men, besides meat technology and science, is their love for hot springs.

They have been hosted each year by an equally interesting man, Francois Blanc, at one of his gambling resorts in Wiesbaden.  It is said that he is the man who made Wiesbaden what it is today.  Jeppe describes Blanc as a mighty wizard with an eye, quick to see the possibilities of a situation, with a brain to plan and a hand to execute.  His ambitions and achievements are great across Germany, yet, Jeppe tells me that his tastes are simple.

His clothes do not attract any attention and he wears his spectacles on the tip of his nose.  He does not pay attention to flattery, yet, he is a hard-headed, silent man without any enthusiasm and equally without any weaknesses.  He keeps lavish tables, yet he himself eats sparingly.  His wine cellar rivals those of the autocrats in Russia, yet, he himself only drinks mineral water.  He is one of the largest gambling hall owners in Europe, yet, for entertainment, he may occasionally play Dominoes and frequently goes on a drive through the countryside with his wife.

It was at their annual visit to Wiesbaden, earlier this year, where Dr. Ed told Jeppe about a monumental discovery.  Dr. Ed is not a huge fan of cured meat since in producing it, nutrition is lost.  That is, of course, especially true of dry cured meat. The new Irish system largely overcomes this by filling the tank with liquid brine. The partial pressure difference between the meat and the brine has the effect that instead of drawing the albumen out of the meat, as is the case in dry curing where the meat is only rubbed with salt, in the mild curing technique, brine seeps into the meat. No albumen is lost. But for the most part, dry curing is practiced with an accompanying loss of nutrition. At a time when most families across the world can not afford to eat meat more than two days a week and where most children go to bed hungry, at least a couple of times a week any loss of nutrition is a problem in any food source. In the current world context, Dr. Polenske believes the most important consideration in evaluating methods of preservation is its effect on the nutritional value of the preserved food. He is obviously not very familiar with the Irish mild cure and in his work, he mainly considered dry curing.

He designed an experiment to study just how much nutrition is lost.  The brine he prepared was a combination of salt, sugar, and saltpeter.  (5)  He put this in three jars with three pieces of meat which he sealed and opened again after 3 weeks, 3 months and 6 months respectively.  When he tested for nitrite, he unexpectedly found it in the brine and the meat, despite the fact that he did not add any. (6)

Dr. Polenske told Jeppe that he was not that surprised to find nitrite in the brine since he knew that saltpeter is a compound of potassium or sodium nitrate.  Nine years earlier a drama unfolded with a discovery by French scientists of bacteria that changes nitrate into nitrite and further into nitric oxide.  In 1882 a team of researchers, Ulysse Gayon from the French commune or town, as we call it, Bouëx in Charente and his 22-year-old collaborator, Gabriel Dupetit, from the town of Auch, Gers, coined the term denitrifying bacteria.  This formidable research team went on to make a number of very important discoveries about denitrifying bacteria. (7)

Nitrification starts with nitrogen gas which is one of the most abundant gasses in our atmosphere and through the nitrification process, bacteria create more complex compounds such as nitrate (codecogseqn-2).  An example of nitrification is ammonia (codecogseqn-7) which is changed into nitrite (codecogseqn-5) and finally into nitrate (codecogseqn-2) which serves as the nutritional source for plants.

Denitrification is the reverse where a more complex molecule is broken down to the point where it ends up with a simple molecule like nitric oxide (NO) or pure nitrogen gas (codecogseqn-6).  Denitrification is, therefore, the reverse of nitrification.  This time it starts with a complex compound of nitrate (codecogseqn-2)  which is changed into nitrite  (codecogseqn-5), into nitric oxide (NO), into nitrous oxide (codecogseqn-8) and finally back into nitrogen gas or molecular nitrogen (codecogseqn-6).  Note the gain or loss of the oxygen atom in both processes.

Louis Pasteur, the renowned French chemist, and microbiologist urged Gayon to follow what happens with the oxygen of the nitrite utilised in the process of denitrification.  They heeded his advice paid close attention to this.  They conclusively refuted an old notion that nitrate was reduced through chemical means by the hydrogen, generated during fermentation.  As to the purpose of the loss of oxygen they believed that the bacteria used the oxygen from nitrogen for the combustion of organic matter to generate  CO2. (8)

Based on their very thorough work, Dr. Polenske believes that nitrite is present through this process of denitrification of nitrate by bacteria.  He expects there to be much public concern following his discovery since nitrite is seen as a poison.  (9)  There is a constant battle from farmers to keep their cattle away from water that has nitrite and in every major newspaper, in every town and city, the nitrite levels in the town’s drinking water are published every week so that citizens know to avoid it.”

Jeppe was now becoming particularly excited. “Eben,” he said and put his hands around my shoulders. In his other hand, he had a pen and started drawing a picture for me on a blank piece of paper on his desk.  “In dry curing we start with nitrate. Sodium or potassium or calcium or magnesium nitrate, depending on where you harvest the nitrate from. We now use it to mix into salt and rub it on the meat to cure in dry curing. What is happening?”

I told him that the nitrate will be turned into nitrite by bacteria. “Yes, yes, yes!” He said impatiently. “But what else? What do you see?” Still, I had no clue what he was talking about.

“Time!” He exclaimed, “It will take time!”

“What is the faster process? Dry curing or mild curing”, he asked.

That one I gladly knew. “Mild curing!” “Correct!”, he exclaimed. “Correct!” “But why?”

Suddenly I saw what he was driving at! “The time it takes the bacteria to convert the nitrate to nitrite . . .” “And what?”, he spurred me on. “What does this points to?” “What is doing the curing?'”

I suddenly saw it and it a bolt of energy hit me. “It is the nitrite doing the curing and not the nitrate!” “The time difference between the old system of dry curing using nitrites and the new system which re-uses old brine is that in the old brine, the nitrate is converted to nitrite! This is the power of the old brine! This is why it is so much faster!”

His secretary walked in at that moment announcing that his next appointment is there. “Oh, let him wait”, Uncle Jeppe exclaimed! “”Get us coffee! There is some hope for South Africa after all!!” He gave me an enthusiastic slap on my back!



He walked around his desk and sat down. “This I did not discuss with Polenski but I saw it immediately! If I told him the entire Germany would convert to mild curing and Denmark’s competitive edge would be lost.  I sat there thinking of what Andreas told me. That I will find that my greatest discovery won’t be the mild curing process, but why it works the way it works. The “why?” And “how?” of curing. I was exhilarated! Like last Friday when I learned about mild curing and the Danish Cooperative model.

Tristan, I know you love biology and the natural sciences. This is why I address this mail to you and I have no worry that I become too technical. The reaction sequence and mode are beautiful. I can honestly say that I am completely in love with the natural world.

I now want to know every element present in the brine, and its exact function. What is the chemistry in the meat itself?  How does curing happen? When we know this, we will be in a position to manipulate the process and improve on it.

My son, you know me; that there is another important point in this story that strikes me.  Right at the start of this journey, I realised that what we are discovering is much more than simply learning how to cure bacon.  This journey back to the lands of my forefathers is a big deal! In a way, it was already an end in itself for me. History and context if of enormous importance. Our lives are never in isolation. We come from the soil of Denmark and the fact that it is here where I find the answers is hugely important to me!

Besides this, bacon is in the center of scientific research of Europe, America, and the United Kingdom, and the combined scientific focus of these countries are directed at unlocking its secrets which are bound up with that of agriculture and superior technology in warfare.  Besides these, there are the many human stories that are part of the story of bacon.  Real people who each contribute to small parts of a very large jigsaw puzzle that is coming together.  They teach us about life. We do not live in isolation, my son! What I am recounting is not fiction! I tell you real stories of real people! Let us pause right here and think about this truth! It is deeper than bacon!

Within the same year of publishing a major paper on denitrifying bacteria by Gabriel and Ulysse, tragedy struck.  The young Gabriel Dupetit’s tragically ended his own life.  He traveled to the Italian city of Savano and booked in at the Albergo Svizzero under the false name, Gaston Dunault.  Overcome by anxiety of all sorts, on the evening of 28 December 1886, he injected poison into himself.  He was discovered, barely alive and despite much effort to save his life, he passed away on the morning of the 29th.  He left a note in French explaining some of his worries.  The use of the false name was done to hide his identity and spare his parents embarrassment.

I am humbled and saddened by this story.  His work directly contributes to our quest of understanding bacon and still, his death reminds me that our lives are bigger than our goals and dreams.  Despite our ambitions, we must pay attention to each sunset and sunrise and never make the mistake of thinking that achieving goals define us.  A man who got this balance right, I believe, is Francois Blanc who seems to find fulfillment in small things, despite his success.  His success does not define him.  He finds the greatest fulfillment in the ordinary in life.  In this, bacon and life become inseparable and I am never sure when I stop learning about the one and start learning about the other.

Maybe, I wonder, the biggest and most important acts of his life was the drives he took through the countryside with his wife. His relationship with his sons and the evenings that Uncle Jeppe and Dr. Polenski spent with him of which Uncle Jeppe tells me that Blanc was really happy.

We don’t understand any of the processes, but identifying the different elements in the brine, including microorganisms, nitrate, nitrite, salt, potassium, and sugar is the basis for understanding the process and should open up the possibility to do it faster and better and safer system without losing quality.  I would love to take back to Cape Town a curing method where curing can be done in a shorter time than 19 days, yielding a product that tastes just as exquisite as Irish or Danish Mild Cured bacon.

Even so, with all the drama offered by our quest, never forget the priority of each sunset. Knowing that we are but small parts of a very big whole. That our highest achievements will be measured in whom we loved and how content we were with whatever life offers us. My heart goes out to that young man and his parents! My heart goes out to him! Imagine his final moments – alone, in a foreign land! With these, my dear son, it is time for me to go. Know that, no matter what, my love for you and your sister is eternal. It will be my last thought when I die. The vision of you and my dear Minette! You guys are my entire world and as certain as I write these words today, one day you will read it and I will be gone. Know that my life was not just about bacon, but like Gabriel Dupetit, it is also about the art of living! Imitate me, my son! Live!!

Be well, my boy!  Take care of Lauren and Minette.

Lots of love from Denmark,

Your Dad.


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(c) eben van tonder

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(1)  “St” is the abbreviation for “stone.”   Until as recent as the Second World War, the Smithfield market in London used the 8 lb to a stone measurement. (hansard.millbanksystems)

The stone weight differed according to the commodity weighed.  Animals were weighed in 14 lb to a stone before they were slaughtered and once slaughtered, the carcass and meat would be sold in 8 lb to a stone measure.  Spices were also sold in 8 lb to a stone weights.  (Newman, 1954)

(2)  A survey was done in the US in the 1950’s to determine the most common brine mix used for curing bacon at the time. (Dunker and Hankins, 1951: 6) Even though it is 60 years after this letter was presumably written, I include it since methods and formulations in those days seemed to have a longevity that easily would have remained all those years later.  The survey was also done among farmers, in an environment where innovation are notoriously slow.

(3)  How salty was this bacon in reality?  The recipe is used by most US farmers by the 1950’s was 10 lb (4.54kg) salt, 3 lb (1.36kg) of brown suger, 6 ounces (170g) of black pepper and 3 ounces (85g) of saltpeter.  10 pounds (4.54kg) of this mixture per 100 pounds (45.36kg) of meat.

The total weight of dry spices is therefore 6.07kg of which salt is 74% or  3.4kg.  This was applied at a ratio of 3.4kg salt per 45kg of meat or 1 kg salt per 13 kg of meat.  Not all salt was absorbed into the meat, but the meat was regularly re-salted over the curing period which means that this ratio would be applied many times over before curing was complete.  Compare this with the salt ratio targeted by us in 2016 of 25g per 1kg final product, this means that the bacon made with this recipe would be extremely salty, irrespective of the use of sugar to reduce the salty taste.  The bacon would have to be soaked in water first to draw out some of the excess salt, before consumed.

(4)  Eduard Polenske (1849-1911) was born in Ratzebuhr, Neustettin, Pommern, Germany on 27 Aug 1849 to Samuel G Polenski and Rosina Schultz. Eduard Reinhold Polenski married to Möller. He passed away in 1911 in Berlin, Germany. (Ancestry.  Polenske)

The Imperial Health Office was established on 16 July 1876 in Berlin,focussing on the medical and veterinary industry. At first it was a division of the Reich Chancellery and from 1879, fell under the Ministry of the Interior. In 1879, the “Law concerning the marketing of food, luxury foods and commodities” was adopted, and the Imperial Health Office was tasked with the responsible for monitoring compliance with it. Established in 1900, the Reichsgesundheitsrat supported the Imperial Health Office in its tasks. (Wikipedia. Kaiserliches Gesundheitsamt)

(5)  Brine is a solution of salt in water.

(6)  Qualitative and quantitative techniques for measuring nitrite and nitrates in food has been developed in the late 1800’s.  (Deacon, M;  Rice, T;  Summerhayes, C,  2001: 235, 236).  The earliest test for nitrites is probably the Griess test.  This is a chemical analysis test which detects the presence of organic nitrite compounds. The Griess reagent relies on a diazotization reaction which was first described in 1858 by Peter Griess.

Schaus and others puts the year of the discovery by Griess as 1879.  According to him,  Griess, a German Chemist used sulfanilic acid as a reagent together with α-naphthylamine in dilute sulfuric acid.  In his first publication Griess reported the occurrence of a positive nitrite reaction with human saliva, whereas negative reactions  were consistently obtained with freshly voided urine specimen from normal individuals.   (Schaus, R; M.D. 1956:  528)

(7)   Gayon and Dupetit’s discoveries include the following:

  • they demonstrated the “antagonistic effect of heat as well as oxygen on the process.”
  • “They also showed that individual organic compounds such as sugars, oils, and alcohols could supplant complex organic materials and serve as reductants for nitrate.”
  •  In 1886 they reported on “the isolation in pure culture of two strains of denitrifying bacteria.”

(Payne, W. J..  1986)

(8)  In reality, the key to understanding the function of the utalization of the oxygen atom is understanding cell respiration.  The purpose of cell respiration is the formation of ATP.  The organism needs nutrients for respiration which is obtained from sugar, amino acids, fatty acids and an oxidizing agent (electron acceptor), oxygen (codecogseqn-9).  Now, in environments where oxygen is depleted (where the rate of oxygen consumption is higher than oxygen supply, the bacteria respire nitrate.  The nitrate serves the purpose of the terminal electron acceptor, a function which is better performed by molecular oxygen, if it is available.  It is not only nitrite that is used by microorganisms in respiration when molecular oxygen is depleted.  Other electron acceptors are sulfate, iron and manganese oxides.

(9)  Dr Ed Polenski’s findings has been published in “Arbeiten aus dem Kaiserlichen Gesundheitsamte , 7. Band, Springer, Berlin 1891, S. 471–474” (


Asheville Citizen Times (Asheville, North Carolina), 20 August 1895.  All information on Francois Blanc was from an article on page 3.

Dunker, CF and Hankins OG.  October 1951.  A survey of farm curing methods.  Circular 894. US Department of agriculture

Jones, Osman, 1933, Paper, Nitrite in cured meats, F.I.C., Analyst.

Drs. Keeton, J. T.;   Osburn, W. N.;  Hardin, M. D.;  2009.  Nathan S. Bryan3 .  A National Survey of Nitrite/ Nitrate concentration in cured meat products and non-meat foods available in retail.  Nutrition and Food Science Department, Department of Animal Science, Texas A&M, University, College Station, TX 77843; Institute of Molecular Medicine, University of Texas, Houston Health Science Center, Houston, TX 77030.

Payne, W. J..  1986.  1986: Centenary of the Isolation of Denitrifying Bacteria.

Smith, Edward.  1876. Foods. D. Appleton and Company, New York.

Schaus, R; M.D. 1956.  GRIESS’ NITRITE TEST IN DIAGNOSIS OF URINARY INFECTION,    Journal of the American Medical Association.

Picture References:

A cargo ship at the Cape: