Why does one bar of chocolate taste so smooth and fruity while another flat and bitter? This variation in flavour is due to the unpredictable and mysterious nature of the cocoa fermentation process. After cocoa pods are split open, farmers leave beans to ferment in wooden boxes or baskets for bacteria and fungi to go to work. Without this process, all chocolate would taste bitter. It’s cocoa fermentation that gives chocolate fine flavour.Problem is, cocoa fermentation is like a “flavour lottery”. Since each farm relies on whatever microbes happen to be in its environment, growers can’t really tell what flavour or aroma their next harvest will have. A fine batch one season could be followed by a disappointing one in the next, leading to wastage and as a result, loss of incomes.
Scientists discover how chocolate gets its fine taste
A new study claims to have taken this unpredictability out of the equation, making for consistently fine-flavoured chocolate.The study was carried out by 13 researchers — a majority from the University of Nottingham and University of West Indies in Trinidad and Tobago, the the rest from the University of Andes, Colombia, and food company CasaLuker S.A. They claim they’ve found a way to remove chance from the fermentation process. Their method cannot boost yield, but showed that treating cocoa beans with a select cast of microbes can reproduce flavour signatures associated with fine chocolate. The findings were published in ‘Nature Microbiology’.Field research was conducted in Colombia, where farmers have been fermenting cocoa for generations. Their product is exported to nearly 70 countries.Three regions were selected: Santander, Huila and Antioquia. Cocoa from the first two share certain fine flavours while beans from Antioquia taste bitter.At farms, the scientists tracked heat and pH shifts, sequenced microbial activity and created models to determine which abiotic (environmental) and biotic (living) factors were responsible for what reactions. What they found cracked a microbial puzzle. It was not known which microbes were responsible for what flavour, but the researchers found nine producing some of the finest notes, including yeasts such as saccharomyces and the bacteria acetobacter and lactobacillus.Armed with the data, the scientists created their own microbial “starter mix” and introduced it to fermenting beans in a UK lab, to see if they could replicate flavours from Colombia. The resultant cocoa liquor impressed professional tasters, who found Santander and Huila’s rich fruity flavours and Antioquia’s bitterness, all coming from their samples. The scientists had, essentially, guided cocoa fermentation to create specific flavours, a trick the billion-dollar chocolate industry could one day use to even invent new flavours.David Salt, one of the authors of the study, said they “found the secret sauce”.“Once you know which microbes drive which flavour notes, you can dial them up or down. This means not only replicating premium cocoa but, potentially, inventing flavours,” he said. Creation of flavours may be an application for the future, but for farmers, the “starter mix” offers immediate relief, by removing unpredictability and guaranteeing the best flavours in cocoa in harvests. Fineflavour beans fetch better prices than bulk cocoa.“This sets the stage for a chocolate industry akin to beer or cheese industries, based on controlled fermentations capable of robustly reproducing unique flavour attributes,” the scientists wrote in their paper.
