Hot chocolate - making artisan chocolate taste even better!

Sunday, 07 July 2019

As chocolate lovers gear up their taste buds to celebrate World Chocolate Day - marked annually on the 7 July – the University of Nottingham and an award-winning Nottingham based artisan chocolatier have teamed up with a group of Colombian female cocoa growers for a project that aims to get the best possible flavour and price from the beans they produce. 

The first samples will arrive at Luisa’s Vegan Chocolates in Sneinton Market in Nottingham early August. Here the beans will be roasted, ground and melted into premium bars of vegan chocolate. The chocolate will then be subjected to industry standard tasting trials for quality and consistency. 

The research is focussed on the fermentation of the freshly harvested beans – a process that takes place in wooden boxes before the beans leave the farm. Using state-of-the-art portable DNA sequencing devices to characterise the different types of yeast and bacteria involved in the fermentation process the research team wants to know how that drives the taste and flavour of premium chocolate.  

The study – ‘Controlling cocoa bean fermentation for enhanced chocolate favour’ – has been funded by Innovate UK. It is led by the University’s Future Food Beacon working in collaboration with the National Federation of Cocoa Growers in Colombia, , Casa Luker in Colombia, the Cocoa Research Centre at The University of the West Indies, and Luisa’s Vegan Chocolates in Sneinton, Nottingham. 

If there is a specific combination of yeast and bacteria that leads to a really good fermentation and a great tasting chocolate then the team may be able to find ways to help farmers to promote the growth of these microorganisms in their fermentation. Conversely, if there are combinations that give the resulting chocolate undesirable tastes then they may be able to find ways to prevent their growth. 

Cocoa bean fermentation 

Fermentation - the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms - plays an important role in the final flavour of the chocolate made from the cocoa beans.


Like a sour dough fermentation in bread making, cocoa bean fermentation is performed by microbes living in the environment of the farm. However, the fermentation is generally spontaneous and uncontrolled. We hope to learn how this fermentation works on the farm in the hope of being able to better control it to provide the farmer with high quality, more flavourful cocoa beans.
David Salt, Professor of Genome Enabled Biology and Director of the Future Food Beacon.

Why Colombia? 

Colombian cocoa is among the finest in the world. Colombia produces just under 1% of the world’s total cocoa. The Colombian crop is classified as 95% fine/flavour cocoa. Fine/flavour cocoa is used by bean-to-bar artisan producers and this premium cocoa market is predicted to expand by up to 10% over the next five years with boutique cocoa - super-premium cocoa – from the South Pacific already selling for twice the average market price.  

The price of ‘super-premium chocolate’ is expected to rise as consumers seek out more intense, satisfying, complex flavours in chocolate to sate the desire for chocolate without the need to consume as much. 

DNA sequencing to improve fermentation 

Fermentation is a vital stage of the post-harvest process. As well as removing the pulp from around the beans it also removes bitterness and astringency so it’s key to the quality of taste, aroma and colour of the cocoa beans. The process is carried out on site by the growers themselves. Controlling fermentation is difficult and results in a wide variation in quality and flavour of cocoa beans. 

Using the innovative hand-held DNA and RNA sequencing device MinION, developed by Oxford Nanopore, researchers and farmers will measure the microbes fermenting the cocoa beans, in order to better understand the fermentation process. 

They can then work with farmers to manipulate fermentation and achieve the best possible flavour for the chocolate maker.

This is a biological process relying on the microorganisms that are present and these will vary from farm to farm and fermentation to fermentation.
Dr Chris Moore, Future Food Technologist and a specialist in genomics

Chris Moore said: “A range of bacteria and yeast that are present around the farm come together in the fermentation to convert the sugars from the pulp into alcohols and acids. These chemicals alter the composition and structure of the beans and changes the flavour of the resulting chocolate. The farmers use their knowledge and judgement to try to make sure that beans are fermented just the right amount.

“We will be monitoring the microorganisms present in the fermentation over time. This will involve extracting DNA from the gooey pulp that surrounds the beans and then sequencing this DNA to identifying what is growing in it. We also want to know where the microorganisms in the fermentation come from, so we are sequencing DNA isolated from the surface of the cocoa plants, the soil on the farm and on the surface of the equipment used in the fermentation process.  By using the MinION sequencer, we can do the sequencing of this DNA out on the farms.” 

Better beans for bean-to-bar maker 

The research team is working with Gold Award winning Luisa Vicinanza-Bedi - Nottingham’s first bean-to-bar chocolatier. Luisa’s Artisan Chocolates picked up a host of accolades at this year’s Academy of Chocolate 2019 Awards. 

A new supply chain between smallholders in Colombia and the premium Nottingham chocolatier will allow them to sell direct to the maker and obtain a better price than they would receive for bulk cocoa sales. This will benefit rural livelihoods, UK business and consumers. 

I’ve tasted some chocolate from Columbia, and it tastes amazing so I am really excited to work with the growers there. Learning more about the fermentation process is something I want to do. I am excited to work with the scientists and the farmers because I do not know about what they do, and they won’t know how to make the chocolate, so it is a learning partnership. I work in the market where consumers appreciate super premium chocolate so I’m sure we can learn from each other and help Colombian farmers find the right price and the right market.
Luisa Vicinanza-Bedi

Story credits

More information is available from Professor David Salt, in the School of Biosciences at the University of Nottingham, on +44 (0) 115 9516339,

Lindsay Brooke
Lindsay Brooke - Media Relations Manager Science
Phone: 0115 951 5751

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