The history and production of sugar are two of the most fascinating topics regarding food culture. We often think of sugar as a basic food commodity that is easy and cheap to produce. Yet, white table sugar is one of the most sophisticated food items in this world. For its production, you need a specific plant with high sucrose content, you need to purify its juice, and then you need to crystallize the syrup in a controlled manner.
For most of the time in history, the only type of sugar Europeans had available was honey. The modern sugar beet didn’t exist until the year 1750. It were German food engineers who had succeeded at breeding a beet with an astonishingly high amount of sucrose. These sugar beets don’t taste pleasant. Their sole purpose is the production of refined sugar and biofuel.
The traditional plant for the production of sugar is sugar cane. The problem with sugar cane is obviously that it only grows in tropical and subtropical climates. It’s native to Southeast Asia where people have been enjoying sugar cane juice since around 4000 years BC.
But just because you are able to extract the juice from a sucrose rich plant, that doesn’t necessarily mean that you have the technology to refine it into pure sugar crystals. Sure, Southeast Asians boiled down the liquid of sugar cane or palm juice until it was reduced to a thick syrup and eventually solidified when cooled down to room temperature. Until today, it’s very common to cook with palm sugar in this part of the world.
However, palm sugar is typically sold as a golden-brown paste. The palm juice gets evaporated at a high temperature until thick and then packaged in blocks. Granulated palm sugar is a recent innovation that Southeast Asians didn’t know how to produce in ancient times.
How the Indians invented granulated sugar
The first ones to discover a way to granulate sugar were the Indians around 400-300 years BC. The word sugar is even derived from the Sanskrit word शर्करा (śarkarā) which means gravel or sand. For the extraction of sugar, the ancient Indians pounded or ground the sugar cane in order to extract its juice. After that, the sugar cane juice was boiled down to a syrup and dried in the sun to slowly crystallize it.
The sun-drying step was the big innovation in this process. If you were to boil the syrup down until all the water is gone, the sugar would melt and turn into a glass. You know this phenomenon from making caramel. The sugar won’t recrystallize when cooled down.
Until today, sugar is typically crystallized by low-pressure or vacuum evaporation. It’s the direct opposite of pressure cooking. While a pressure cooker increases the pressure and thus lets the water heat above 100 °C without boiling, the vacuum pump decreases the boiling point of water. The water can thus be evaporated at a much lower temperature than 100 °C so that there is no risk for the sugar to melt or caramelize. Before the usage of vacuum pumps, there was always a large amount of melted sugar which had to be discarded in traditional sugar refineries.
How sugar made it’s way to Europe
The Indians first taught the Chinese how to produce crystalline sugar. From there, the knowledge spread through the Middle East until it reached Europe, where sugar cane was first grown in Cyprus by the 10th century. However, it wasn’t really a large scale production. The demand for sugar in Europe had been low and it was just another commodity for the wealthy classes.
It is very labor-intensive to produce sugar and for Europeans at that time, it was not worth the effort. During the 1390s, a better sugar press was developed in Europe which helped to obtain double the amount of juice from the cane. This made it much more profitable to grow sugar cane in a climate that was not ideal. Yet there was no one willing to work on the sugar plantations.
The Portuguese had acquired the island Madeira at that time which is famous nowadays for its wine production. Yet it was also suitable for growing sugar cane. The solution for the labor shortage of the Portuguese was quite simple: Buy African slaves. It was by no means a novel idea at that time. The slave trade had existed long before and was not solely limited to the African continent.
However, it was very convenient to use African slaves. You didn’t have to ship them very far and they were easy to acquire because the African elite made good money from the slave trade. It was by no means only the Europeans who took a profit. They didn’t travel to Africa and caught people in the wild. The slaves were sold like a commodity by other Africans. Sadly, many African nations were even upset when the slave trade was abolished by European countries. It was their most profitable business.
After the abolition of the slave trade at the beginning of the 19th century, the Europeans started to colonize the African continent under the pretext of freeing the slaves in Africa. Of course, this was only a lame excuse to get access to the huge amount of natural resources the African continent had to offer. The African businessmen who had once made a fortune selling slaves to Europe suddenly lost all their power with the invasion of Africa. By 1914, Europe controlled 90 % of the African continent. European powers achieved their goal of abolishing slavery. However, while they were at it they also acquired huge amounts of raw materials like copper, cotton, rubber, palm oil, cocoa, diamonds, tin, and tea.
No slaves, no sugar
But let’s look back at the time when slaves were a necessity for European sugar production. As you might know, Madeira is a small island. By 1490, this island was the main European producer of sugar. In 1492, an Italian explorer was about to change that. It was Christopher Columbus who discovered the Caribbean island Hispaniola. Today, this island consists of two states: Haiti and the Dominican Republic. It was only on his fourth journey to the New World that Colombus reached today’s Honduras on the American mainland.
The European Empires quickly discovered that sugar cane could be grown very well on the Caribbean islands. And there were actually people living there already. It is estimated that between 400 000 to 1 million people used to live in Hispaniola when Colombus first discovered the Island. Roughly 50 years later, in 1542, less than 200 of them were left. The Europeans had tried to enslave the local population for the production of sugar. But these people were no good slaves. They weren’t resistant to old world diseases and they were not suitable for hard physical work.
But luckily for Europen people, it was easy to acquire African slaves and ship them to the Caribean Islands. The triangle trade started and made a lot of Europeans very rich. Slaves were not only deported to the Caribbean islands but also in large amounts to South American countries like Brazil, where coffee was one of the most important commodities. It was an unlucky situation for the African slaves. They were resistant to disease and capable of hard physical work. In the eyes of European colonialists, they were the best “product” on the market.
The history of racism
Prior to the triangle trade, there were no human race theories. Europeans had seen Africans as equal human beings most of the time in history. There was a rivalry between religions. But people weren’t categorized as being of a different race based on physical features. There were only barbarians and inferior religious movements.
Then, during the time of the European colonialization of the world, European explorers got to know a lot of new ethnicities. They saw that there were large physical and cultural differences between different ethnic groups. The race theories were not always there to discriminate against people. Even scientists at that time believed in the existence of different human races. Today, we know that there is only one human race.
Until the late 20th century, it was normal to call black people “Neger” or “Mohr” in Germany. The word “Neger” itself is of Latin origin and just translates to black. It was used in some cases to discriminate against black people but it was also used by other members of society without any negative connotations. It was around 1975 that the word started to slowly disappear. It was replaced with the German word “Schwarzer”, which also translates to black.
The race theories started to become racist once the European colonialists started to use them as a way to differentiate themselves from African slaves. It’s not so easy to torture other human beings. But if you look at them as an inferior race or “product” it becomes much easier to do so. It was a big no-no to enslave people of one’s own ethnicity. But with Africans, it was fine in the eyes of the colonialists. They were not seen as equal human beings anyway.
The European colonialists were among the first ones to use race theories to justify violence and cruelty. Over the course of history, many emperors and dictators also applied this concept all around the world. Hitler attempted to eradicate jews based on crude racial theories. The Cambodian emperor Pol Pot was known to be an extreme racist. He sought to remove all ethnic and religious minorities from the Kingdom of Kampuchea. As a result of the Opium Wars, the Chinese empire gave birth to the idea of a yellow race. Since the 1850s, China progressively transitions from a diverse multicultural empire into a homogenous country of “superior” Han Chinese.
The history of sugar is a story of slavery and racism
I know that this post is about the history of sugar but I think it is one of the best ways to understand the history of slavery and racism in Europe. Europeans had discovered the New World. But obviously, the European population wasn’t interested to move there to start a life as a simple worker on a sugar plantation. I mean, who would? The only thing European settlers were interested in was the executive positions. This created a huge demand for slaves from Africa because the local population of the Americas was not suited for the work on plantations.
Between 1450 and 1850, 10 million Africans were brought as slaves to the Americas. About two-thirds of them died on the journey across the Atlantic ocean. But it was still a profitable business. One African slave was able to produce between 3 to 4 metric tons of sugar each year. If a slave lasted two years, the break-even point was reached. On average, a slave worked on a sugar plantation for 5 years.
Over time, it became harder and harder for the European colonialists to keep the rising number of slaves under control. The slave revolt and Haitian revolution in the late 1790s was the beginning of the end of the European sugar cane production in the Caribbean. France lost its former colony, the world’s biggest sugar producer, and the sugar industry collapsed.
Of course, other countries now had the chance to shine. Cuba and Louisiana became major sugar cane producers.
A new source of sugar emerges
In 1833, the British Empire abolished the slave trade. France and Spain followed shortly after. There was a new way to produce sugar in Europe now: the sugar beet. The beet sugar industry was developed by the Prussian Empire. Germany wasn’t a huge colonial power so that it was in search of a way to produce sugar locally.
In 1747, the Prussian scientist Andreas Sigismund Marggraf discovered that beets contain the same kind of sugar as sugar cane: sucrose. Yet, the sugar content in regular beets was too low to be profitable. Through selective breeding, the sugar content in beets was raised from 8 to 16 percent by 1800. Today, a sugar beet usually has a sugar content between 18 to 20 percent. That’s comparable to sugar cane, which has a sugar content between 10 to 20 percent.
In 1801, Franz Carl Achard, a student of Marggraf, opened the world’s first beet sugar factory in Silesia. In comparison to cane sugar, beet sugar was not profitable. Yet it was funded especially by the French government. The production process was refined overtime to make beet sugar production more effective. Around the year 1850, beet sugar was finally able to compete with imported cane sugar. This led to a dramatic drop in prices which made sugar affordable for anyone in Europe.
Until the year 2017, the EU had a so-called “sugar-quota”. It set a high minimum price for sugar which made the sugar beet an attractive crop to grow with high-profit margins. There was no production limit for producers. Any excess could be exported to obtain even more profit by local sugar producers.
Nowadays, European sugar producers have to compete with cheaper-priced cane sugar. While the EU is the world’s leading producer of beet sugar, only 20 % of the world’s production is beet sugar. I’m sure we will see a huge decline in the sugar industry in Europe in the upcoming decades. The EU has protected the trade interests of European producers for many years but the last years have shown that the golden age for European sugar, dairy, and alcohol producers will slowly come to an end.
What sugar will look like in the future
We Europeans can be happy that we still get to eat real sugar. Until today, 90 % of sweeteners used in global food manufacturing is sucrose from sugar beet or sugar cane. It’s quite shocking that one of the richest countries worldwide, the USA, is the great exception to the rule. In the US, high-fructose corn syrup has replaced sucrose in half of the food products because it is cheaper, and well, the US has a surplus of corn.
Since the fall of the EU sugar quota, glucose-fructose syrup, Europes version of high-fructose corn syrup (made from corn and wheat), can be produced in unlimited amounts. The supply is not large enough yet so that it isn’t used as a primary sweetener by local manufacturers. But we will see its rise all over the world in the upcoming decades. Sucrose gets quietly replaced with cheaper high fructose corn syrup in many industrial products worldwide.
Corn doesn’t contain large amounts of sucrose like sugar cane and sugar beets do. But it contains a lot of starch which can be broken down by enzymes to produce glucose. Now, sucrose is a 50/50 mixture of glucose and fructose. To produce high-fructose corn syrup, 42 % of the glucose gets converted to fructose by the enzyme glucose isomerase. The resulting syrup is therefore very similar in composition to traditional sucrose syrups made from sugar cane or sugar beets. The industry can enhance the fructose content even further to amplify the sweetness of the syrup by liquid filtration. The resulting 90 % fructose syrup can then be ‘diluted’ with glucose syrup to produce a syrup with the desired level of sweetness.
You might ask yourself where the 42 % come from. This is roughly the upper limit you can achieve for the enzymatic reaction with glucose isomerase. Chemical reactions are often reversible and occur in both ways. Once an energy equilibrium is reached, the rate of glucose that gets converted to fructose is the same as the rate of fructose that gets converted back to glucose. Chemical and biological processes always strive to achieve an energy equilibrium. You can push that equilibrium in one or the other direction by changing the process conditions like for example the temperature or pressure. However, this equilibrium state always remains the limiting factor of how far you can concentrate the fructose by enzymatic reactions.
In the video below, the production process for high-fructose corn syrup is nicely illustrated. I tried to find a video with an actual production plant but somehow couldn’t find one.
How conventional sugar is made
The production process for cane and beet sugar is pretty straightforward. You don’t need to alter the chemical structure of the sugar. It’s already a 50/50 mix of glucose and fructose. The conventional sugar production is all about extracting the sugar crystals from the beet or cane juice.
The beets or cane get harvested, washed, and crushed into small pieces. Then the juice is extracted via a mill. It gets bleached with sulfur dioxide vapor and subsequently treated with milk of lime. Milk of lime neutralizes the natural-occurring acids in the juice. This leads to the formation of insoluble lime salts which can be separated from the juice. Adding to that, the juice also gets heated to boiling so that the proteins, fats, waxes, and gums coagulate and precipitate.
The clarified juice gets filtered to remove impurities which are referred to as mud. In an evaporator, the clear juice gets concentrated from an initial sugar content between 15-20 % to about 60 %. You might know it from reducing a sauce or cooking broth, that further impurities will rise to the top. These can simply be skimmed off after evaporation.
Now, it’s time to crystallize the sugar. A small amount of sugar crystals is added to the syrup to induce crystallization. In a vacuum evaporator, water gets evaporated over moderate heat to prevent the caramelization of the sugar. The solution becomes supersaturated with sugar so that the sugar falls out of solution and a crystalline paste forms that is called muscovado. In a centrifuge, the sugar crystals are then separated from the molasses. The sugar is still wet and clumpy at this point so that the crystals get dried in the last production step.
The science of crystallizing sugar
Before the invention of vacuum evaporation, the yield in sugar refineries was much lower. As you might know, dissolved sugar raises the boiling point of water. At extremely high sugar concentrations, the syrup can get hot enough for the sugar to melt and caramelize. It won’t recrystallize then. For lower sugar concentrations up to 60 %, the syrup can’t be heated above roughly 100 °C at atmospheric conditions so that it is safe to use a regular evaporator. However, at a concentration between 80-85 %, the sugar solution can already be heated up to 110 to 115 °C. This is when sugar will start to melt.
A vacuum evaporator lowers the boiling point of water by removing air from the atmosphere. The air is “pushing” against the water under atmospheric conditions. Therefore, more energy is required to evaporate it. By removing these air molecules (creating a vacuum), there is suddenly space for the water molecules to migrate to. Therefore, less energy is required to vaporize the water.
The actual crystallization process is started by sugar crystals which are added to the syrup before vacuum evaporation. Crystallization happens spontaneously in supersaturated solutions, however, it might take a long time. Seeding crystals get the nucleation process started at the desired supersaturation level and act as a template for the desired particle size. In a supersaturated solution, the sugar molecules move around randomly and might spontaneously crystallize when they aggregate. This can take a long time to happen and the crystal structure will be random. Seed crystals eliminate the need for spontaneous nucleation. They get the crystallization started right away.
It’s very important to start the seeding process at the right supersaturation level as this will determine whether you get many fine particles or one big glob of sugar. Nucleation, the formation of new crystals, is favored at high supersaturation levels while at low supersaturation levels close to the solubility curve, crystal growth is favored. Rock sugar is produced by slowly letting a slightly supersaturated solution of sugar grow into large crystals. Granulated sugar is the direct opposite. The sugar gets crystallized quickly at a high supersaturation level to obtain many small crystals.
What a sugar refinery looks like
Sugar production is a very fascinating technology. But I don’t want to deep dive into every aspect of it. In order to keep this post digestible, I didn’t talk about the scientific aspects of cane or beet juice extraction and the clarification steps. I intend to do that another time in a post about fruit juice which is also a fascinating topic. Even if we don’t always see it as consumers, orange, apple, and all other fruit juices are very complex systems. The industrial food production processes are anything but trivial.
So let’s wrap up the production process of granulated sugar with two videos. Discovery UK has published an excellent educational video about the production process for cane sugar:
If you want to see the process for sugar beets, here’s a great video:
Bonus: Palm Sugar
As a little bonus, I want to briefly discuss the production of palm sugar. It’s a popular sweetener in Southeast Asia but can also be found in other regions like India, Africa, South America, and the Caribean Islands. Palm sugar gets produced from the juice of palm trees just like maple sugar gets produced from the juice of maple trees or opium gets produced from the juice of poppy plants. There are five different kinds of palms which can be used to acquire palm sugar:
- Palmyra palm
- Date palm
- Nipa palm
- Sugar palm
- Coconut palm
The juice of these palms contains up to 15 % sucrose. The raw juice gets sieved and boiled down to a thick syrup. Once the solution is heavily supersaturated, the crystallization process starts. It’s no tightly controlled crystallization like you know it from granulated sugar. Of course, big industrial producers use seeding crystals and work with exact temperatures and strictly defined supersaturation levels. However, artisanal palm sugar production is not as sophisticated.
Some of the sugar will melt, some might even caramelize because of the high temperature. You end up with a thick paste that is partly crystalline and partly a glass. The evaporation process is stopped once the sugar concentration reaches about 80-85 % and the water has reached a boiling point of about 120 °C. The palm sugar is then aerated to cool it down quickly and poured it into molds.
Water at a high temperature can dissolve more sugar than at a low temperature. So while the palm sugar cools down, the level of supersaturation will increase even more. The sugar crystals in the solution still continue to grow while the paste cools down. Producers need to stir the palm sugar paste vigorously to prevent the growth of any larger crystals. The vigorous stirring guarantees a smooth and creamy texture with many tiny sugar crystals. By stirring the mixture, the crystals already present in the hot palm sugar act as seeding crystals when they come in contact with other sugar molecules. The more smaller crystals are formed (nucleation), the less free sugar molecules are left in the solution to “feed” the already existing crystals.
It’s hard physical labor to produce palm sugar if you do it by hand. Just take a look at the video below:
I could continue to talk about sugar for years. But let’s stop here for today. Artificial sweeteners and candy production are topics for another blog post, I guess. Yet, you’ve made it to the end of this post. So I assume it was at least an interesting read.