Overlooked & Underestimated - How a pioneer in chemical engineering made our lives sweeter

When we have a craving for something sweet and go to our favorite sugary treat we likely don't think about the history or process it took for the sugar cane to become the delightful sweet crystals we know and love or loathe today.

ScientificAmerican explains that sugar was once a luxury item restricted to the wealthy. High prices were the result of limited supplies, and those limits existed because sugar processing was arduous and dangerous. On plantations, sugarcane juice was boiled to evaporate out the water, eventually producing sugar crystals. Enslaved workers scooped the thickening liquid from one open cauldron to another to increase its concentration. Their working conditions were sweltering, injuries were common, and fuel was costly. Yet this was the standard method of production until a clever Louisianan named Norbert Rillieux upended it.

So who was Rillieux? Born in 1806; his mother was a free woman of color, and his father, Vincent Rillieux, was a European American plantation owner and inventor. At that time, 25 percent of African Americans in New Orleans were free and mixed couples often raised families together. Norbert Rillieux was educated in Paris since New Orleans schools would not admit him. He excelled in engineering, particularly on projects that employed steam. In his day, steam-powered society. He wrote papers about steam engines and ways of maximizing the vapor in a vessel heated by steam. While in Europe, he also theorized about ways to improve the evaporation of sugar juice, a process he became familiar with when he was a boy. He returned to New Orleans to apply these ideas.

Rillieux devised an effective mechanized multistep method for juice production. Instead of using people to transfer liquid with increased sugar content from one cauldron to another, he connected several sealed vacuum pans together with pipes and linked one of those pans to a steam engine. Instead of heating each individual pan with a flame below it, steam from the engine boiled the liquid in the first pan. The vapor produced during that evaporation process wasn’t wasted, but instead directed through a pipe to the next pan and used to heat it. Each successive pan was heated by the vapor of the previous pan. The sugar liquid, which also flowed from pan to pan, increased in concentration with each step and this process saved fuel. Lastly, Rillieux employed the thermodynamic principle that pressure and temperature follow each other—as one changes so does the other. By lowering the pressure of each successive pan, he lowered the temperature needed to boil the juice, which prevented the sugar from caramelizing. 

The inventor revolutionized sugar processing by taming steam and thermodynamics. Rillieux’s apparatus—now called the multiple-effect evaporator—is used in modern industries worldwide, such as food processing, chemicals, and pharmaceuticals. His name was once well-known, and many sugar-processing firms in the 19th century prided themselves on using a “Rillieux system,” but references to him evaporated in the last century.

In short, the Rillieux system was of the same magnitude as Eli Whitney’s cotton gin. And here is the bazaar twist: Rillieux became the most sought-after engineer in Louisiana: evaporator was embraced widely yet, as a “person of color,” and as the Civil War drew near, Rillieux faced an increasing number of restrictions, such as the loss of his right to walk along the street. So, Rillieux moved back to France where he died in 1894. Where Eligh Whitney has made his way into the annals of history. Norbert Rillieux is forgotten. But one thing is as clear as simple syrup, this pioneer in chemical engineering made our lives much sweeter.

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Chemical engineeringEvaporatorHistoryInventorSugarSugar cane