The eccentric engineer: Norbert Rillieux and the Sugar Revolution

It’s fair to say that people of colour in Louisiana don’t have a great deal of reason to be thankful for the sugar plantations that helped make the state wealthy, and yet it was one of their own who transformed the sugar industry the world over, improving both the product and the lot of the enslaved people forced to produce it.

Sugar cane growers in the early 19th century had a problem. The raw cane juice was turned into sugar in a process known as the ‘Jamaican Train’. Initially, juice was boiled in a large kettle until most of the water had evaporated. The resulting syrup was then ladled by hand into a series of ever smaller copper evaporating pans until just the crystalised sugar was left. At least that was the theory, but there were numerous problems.

The dangerous job of ladling hot syrup from pan to pan led to large numbers of injuries among enslaved workforces. From the point of view of the owners, the process led to spillages and considerable loss. Finally, the product was not always saleable, as controlling the temperature of the fire under the pans was haphazard; often, syrup rose about the temperature at which it caramelised and burnt, creating a dark, bitter product.

The solution came not from a plantation owner, but from Norbert Rillieux. Rillieux was lucky by the standards of his day. Born the son of a ‘free person of colour’ and a white plantation owner, his opportunities were worlds away from those of the enslaved people who worked on his father’s plantation. He had received the good education afforded to the gens de couleur libre in the state, which had enabled him to follow his dream of studying engineering at the famous École Centrale in Paris.

He become an expert on steam engines, taking a job as instructor in applied mechanics. It was here that he came up with an idea for solving the sugar refining problem.

Word soon got back to Louisiana about Rillieux’s research, and plantation owner Edmund Forstall offered him the job of head engineer at his new sugar plantation, then still under construction. For the grandson of an enslaved Louisianan, it was an astonishing turnaround, but Rillieux’s refining complex was never finished due to arguments between the principals.

Undaunted, he continued improving his designs for a machine that could refine sugar safely. The result was the multiple-effect evaporation system, which finally proved its worth in 1845, when a working system was installed on the Myrtle Grove Planation in New Orleans. The system was as brilliant as it was simple.

Firstly, Rillieux avoided the problem of burning sugar syrup by using a vacuum pump to reduce atmospheric pressure in the boiling vessel. As the syrup boiled at a lower temperature, it never reached the point where it caramelised and burnt. The evaporation pans were stacked, each higher chamber with a slightly higher vacuum, and hence lower boiling point. As the bottom pan was heated, it released steam, which was used to heat the pan above and so on.

This proved not only far more controllable but reduced the fuel costs by around three-quarters. As there was no ladling between pans, there was also no spillage and, most importantly, there were no more accidents. Rillieux patented his first machine in 1843 and the enormous savings and improvement in quality it made soon saw the device installed across Louisiana.

As perhaps the greatest early development in chemical engineering and a process still basically used to this day, one might expect the Louisianan sugar producers and refiners to be grateful. But with the Civil War approaching, this proved far from true. Barred from ‘polite’ Louisianan society, the gens de couleur libre were increasingly restricted, paying the same tax as white inhabitants, but their children were barred from public schools and individuals required a permit simply for walking abroad in New Orleans.

Increasing hostility towards free people of colour also affected Rillieux’s work, the final straw coming when he had a patent refused on the grounds that he must be a slave and thus incapable of holding a patent.

With that, Louisiana’s most brilliant engineering son left the country, returning to Paris. Here he introduced a similar system for the sugar beet used in Europe, as well as spending a decade working with the family of Jean-François Champollion on the decipherment of Egyptian hieroglyphics. Meanwhile, the USA descended into bloody civil war from which at least the enslaved plantation workers would finally emerge free.