100 Years? Piece of Cake

Article by Séamus Higgins AFIChemE and Ellie Cooke

Séamus Higgins and Ellie Cooke look at a century’s evolution of food and processes, in the form of a chocolate birthday cake

AS this month’s IChemE Centenary theme focuses on food and water, we look at how the basic food ingredients of a chocolate birthday cake – flour, sugar and chocolate – have evolved over centuries and more recently developed over the past 100 years.

For millions of years, food has not only fuelled our evolution, it has also dictated the way we live; from hunter-gatherers to agricultural societies to our current industrial world. Beyond sustenance, food is also a centrepiece of tradition and plays a key role in our celebrations and folkloric festivities.

Likewise, with food process engineering and IChemE! When one looks at the symbolism of IChemE’s coat of arms, the shield is divided into two parts representing the profession as a whole. The salamander, on the left, represents the “fiery” arts of chemistry (the crucible of medieval extractive metallurgy was called a salamander), while on the right the mill rind is symbolic of engineering – as grain milling represents the most ancient continuous process.

(Left to right): Was Vitruvius the world’s first food process engineer?; Late 19th Century four-roller flour mill


It was around 25 BC when Vitruvius, a Roman engineer/military architect, detailed the first undershot vertical water wheel to power a set of horizontal millstones by way of a 90o gear mechanism, for the milling of grain. It was the world’s first engineered process, purposely designed to operate without being powered by man or working animals, and specifically designed for food production.

When Leonardo Da Vinci later immortalised Vitruvius in the 15th Century, combining ideas about art and architecture, human anatomy and symmetry in one distinct and commanding image, entitled Vitruvian Man, the same Vitruvius could also have been celebrated as the world’s first food process engineer!

In 1887, a Swiss-educated, German engineer, Gustav Heinrich Simon, better known in the UK as Henry Simon built his first mill plant for McDougall Brothers, in Manchester, based on what was referred to as the “gradual reduction” milling system to produce a white flour using steel rollers as opposed to stone.

It was around the same time he formed a partnership with Adolf Buhler of Uzwil, Switzerland for the production of machinery as per his designs. By the end of the First World War, Henry Simon & Co had already installed over 400 mills worldwide.

Today, the Buhler Company of Switzerland, still family owned, is represented in over 140 countries worldwide and is a world leader in both milling and chocolate-making technology.

While the art of flour milling itself hasn’t changed much over the last century, one could point to a number of engineering innovations that have led to a safer, more efficient milling process. Such as the adoption of pneumatic conveying in the mid-20th Century to move product more efficiently through the mill. Another innovation, saving on capital costs, was the double high-roller stand, which provides two grinding passages without any intermediate sifting. More recently with advances in sensor technology and machine learning capabilities, colour-sorting technology uses multiple visible wavelengths to detect the subtlest colour variations in grain to remove foreign particles and damaged kernels at high speed and volume from the mill flow.


The profitability of “white gold” led to Dutch, English and French slave plantations in the Caribbean by the 17th Century, such as this one in Cuba

Sugar, as we know it today, has been around a long time; it was in 510 BC when the Emperor Darius, of what was then Persia, invaded India, where he found “the reed which gives honey without bees”.

Sugar was only “discovered” by western Europeans as a result of the Crusades in the 11th Century AD. Crusaders returning home talked of this “new spice” and how pleasant it was. In 1319 AD it was recorded that sugar was available in London at “two shillings a pound”. This equates to about US$100/kg at today’s prices so it was very much a luxury and expensive “spice”.

It was this supply potential, in the early 16th Century that encouraged Portuguese entrepreneurs to begin exporting slaves to newly-discovered Brazil where they rapidly began growing a highly profitable crop. By the 17th Century, the Dutch, English and French all had their own sugar Caribbean slave plantations with production surpassing even that of Brazil.

Growing demand for sugar in Europe, as a result of the increasing popularity of tea and coffee, also encouraged further growth and profit earnings creating the term “white gold”.

It was Britain’s naval blockade of Napoleonic France at the start of the 19th Century that prodded the French to seek an alternative to Caribbean sugar supplies and gave birth to the European sugar beet industry.

The 20th Century has seen this traditionally heavily subsidised and tariff-protected sugar beet industry grow to produce approximately 50% of Europe’s sugar, including the UK. In 1957 the enzyme glucose isomerase was created in Japan which enabled the production of “high fructose corn syrup” from corn starch. It was introduced in the US food supply in 1970 due to escalating cane and beet sugar costs, and today is used in almost every packaged food and soft drink that US consumers see today.

Unfortunately from a health perspective, consuming too much sugar may lead to health issues. The average consumption of sugar per person has risen dramatically over the past two centuries from just 8 kg in 1800 to 27 kg in 1900. It currently stands at just over 45 kg/y and accounts for a staggering 20% of all calories consumed. 


When Cortés returned from the Americas to Spain in 1528, unlike Columbus, he brought not only the beans but the recipe and the equipment necessary to make the Aztecs’ original chocolate beverage. It is suggested that the Spanish created the word “chocolati”, instead of using the original Aztec word, “cacahuatl”. Authors of The True History of Chocolate, Sophie and Michael Coe, surmise that the Spanish substituted the Mayan word because they were uncomfortable with a thick, dark brown drink that began with the Spanish word “caca”!

In 1615, cocoa found its way into the court of King Louis XIII and in 1657, the first English chocolate houses opened, much like today’s coffee houses. The inventor of “chocolate for eating” is unknown, but in 1847 Joseph Fry of Bristol discovered a way to mix cocoa powder, sugar, and cocoa to create a paste that could be pressed into a mould. The resulting bar was a commercial success and people enjoyed eating chocolate as much as they did drinking it. John Cadbury created a similar product in 1849.

By today’s standards, the original bittersweet chocolate bars of both Fry and Cadbury would not have been considered very palatable.

That only happened in 1875 when Daniel Peter, a Swiss chocolatier and close friend and neighbour of Henri Nestlé, in Vevay, Switzerland, succeeded in mixing cocoa paste with Nestlé’s already-sweetened condensed milk, thereby creating the world’s first milk chocolate bar.

(Top to bottom) Non-conched (manually ground) chocolate; granite roller and granite base of an early 1900s ‘conche’; modern refined chocolate

In 1879 another Swiss chocolatier, Rudolf Lindt, inadvertently left a mixing machine on over a weekend and “discovered” a much smoother textured chocolate. He went on to develop a new mixing machine resembling a conch shell to process his chocolate, and the process of “conching” chocolate became a global standard for quality chocolate manufacture.

The scaleup of chocolate production and product nuances over the past 100 years has been another challenge for process engineers and food scientists alike. Just think of novel chocolate bars like Aero: are those bubbles just random, or sized to specification? When it comes to chocolate liqueurs, how do you ensure the liquid won’t eventually leak?

Along with conching, there are many other operations involved in the complex engineering process of chocolate manufacturing. Even once the chocolate has been produced it must be correctly tempered – cooled and reheated during mixing to create a material that will solidify in a correct form once cooled. The cooling of chocolate must be carried out at a specific rate to ensure the right crystal form is created and to solidify the unstable fats so they cannot change form. Going forward, another challenge will be to reach a manufacturing process that is zero carbon.

To this day the Swiss are still the biggest consumers of chocolate, each averaging 8.8 kg/y. Globally, chocolate consumption is estimated to be 7.2m t/y (with an approximate sugar content of 50%). And consumption is still growing at an estimated 2–4% compound annual growth rate.

As Michael Levine, Global Food Solutions CEO, put it: “Chemically speaking, chocolate really is the world’s perfect food.”

Article By

Séamus Higgins AFIChemE

Associate Professor for Food Process Engineering at the University of Nottingham

Ellie Cooke

Engineer at Mondelez Chocolate Discovery

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