Introduction 

It is necessary to gain a profound understanding of the components of chocolate in order to create distinct and delicious chocolate flavours. There are many factors to consider here, from the type of cacao used to the terroir where it is grown. In addition, the flavour profile evolves as the process progresses. 

After selecting high-quality cacao beans with great flavour potential, it is time to process them with care so that the natural flavour of the beans is maintained. This includes harvesting, fermentation and drying.

In the previous blog series we explored how origin and terroir have an impact on the chocolate flavour profile and the influence of cacao variety and genetic on the chocolate flavour profile. 

Harvesting

The cacao harvest is an essential step in the flavour development process. Cacao beans are harvested when they are fully ripe and are then fermented for several days to bring out their natural flavours. 

The timing of the harvest will affect the flavour of the chocolate, as the beans will be at different stages of maturity and will be exposed to different environmental conditions.  

Once the pods are harvested by hand, they are cut open. The beans are surrounded by a sticky sweet pulp, which provides food for the germs inside the beans (which will trigger fermentation) and when tasted, have a tropical, bubblegummy, sugary flavour. The beans are very bitter and tannic at this stage, as a natural defence mechanism.

Fermentation 

Fermentation is an integral part of cacao production as it plays a major role in the flavours of the resulting chocolate. However, achieving successful, even flavour development requires skill and knowledge on the part of cacao farmers.  

The fermentation process helps to develop the flavours of the beans as well as reduce bitterness. During fermentation, a number of biochemical reactions occur, resulting in flavour precursors such as free amino acids, oligopeptides, reducing sugars, and others. These precursors are then involved in Maillard reactions during cacao roasting, leading to the formation of various chocolate flavours. The concentrations and the ratio of the flavour precursors at the end of fermentation have a significant impact on the development of flavour volatiles during roasting. 

As soon as the cacao pods are opened, the fermentation process starts, necessitating careful consideration by the farmers as to when to open pods, where fermentation is to take place, and how long fermentation will last. Various fermentation methods, such as platforms, heaps, baskets, trays, and boxes, exist and can each influence the development of flavours in the cacao beans.

You can discover how each step of the cacao process, from harvesting to fermentation and drying, is essential to produce the highest quality cacao beans to make the best chocolate.

The fermentation process starts with an anaerobic phase (absence of oxygen), occurring in the first 24 to 36 hours following harvesting and opening of the pods. This exposes the beans and pulp to numerous microorganisms. Yeasts, bacteria (lactic acid bacteria, acetic acid bacteria, and Bacillus species) and fungi are among the organisms involved in the process. Sugars like sucrose, glucose, and fructose are converted to ethanol through alcoholic fermentation, catalysed by the yeasts, similarly to brewing. During the anaerobic phase, sucrose is partially broken down to reduce sugars, proteins become peptides and amino acids, and polyphenols are hydrolysed and oxidised.

The second phase of the cacao fermentation is the aerobic phase (with oxygen present). The fermentation produces lactic acid, acetic acid, ethanol and carbon dioxide. Towards the end of the 2nd phase, lactic acid bacteria are replaced by acetic acid bacteria which oxidise ethanol to acetic acid, hence the vinegary aroma. This process heats the cacao to 45-52 °C, which is important for the development of flavour. 

The amount of flavour precursors and therefore quality of cacao can vary greatly depending on the fermentation method, length, speed, pod storage, and cacao genotype. 

E.g. Box fermentation involves stirring the beans daily for even fermentation, reducing mould risk and increasing oxygen. This increases the aerobic phase of fermentation, leading to more acetic acid in the beans, making them potentially taste more acidic. To limit this, box fermentation processes may shorten fermentation time and reduce turnings.

The importance of a good fermentation on cacao flavour profile: 

🔸Under-fermentation: lack of flavours, medicinal and woody notes, tannic and bitter.

🔸Over-fermentation: meaty, sweaty, yeasty or putrid cheese notes. 

🔸Uneven-fermentation: mix of off-notes, farmy or putrid notes. 

🔸No-fermentation: lack of flavours, bitter, astringent. Some cacao beans have no or very little fermentation such as some Mexican Criollo cacao varieties.   

If you want to explore chocolate flavours, Check out Cocoa Runners' website for a wide range of bean to bar fine chocolate makers, virtual tastings and subscription services. 

E.g. For comparison of same beans with different fermentations: 

🔸Krak Chocolade – Socunosco, Mexico 5 Day Fermentation chocolate bar

🔸Krak Chocolade – Socunosco, Mexico 6 Day Fermentation chocolate bar

🔸Friis-holm - Chuno, double-turned, Nicaragua 70% chocolate bar

🔸Friis-holm - Chuno triple-turned, nicaragua 70% chocolate bar

Drying 

The beans are then dried in a controlled environment to reduce their moisture content, which helps prevent mould growth and preserve their flavours. This phase also plays a significant role in reducing bitterness, astringency, and acidity of the cacao beans, as well as developing their characteristic brown colour.

It is important to aerate and dry the cacao beans properly. If the drying process is too quick, the beans will maintain a high level of acetic acid created during fermentation, resulting in a very acidic taste. To ensure a more pronounced chocolate flavour, controlled and protected sun-drying is the preferred method over artificial drying, which can lead to off-flavours such as smoky, hammy, rubber, or gasoline.

Well-dried, high-quality beans offer the finest flavour profile, with minimal sourness, bitterness, and astringency, a distinctive brown colour, and by the lack of off-flavours, like smoky notes and too much acidity.

Conclusion 

For entrepreneurs in the food industry, discovering how the cacao process influences chocolate flavours is crucial for bringing out the distinctive flavours in the final product. 

As we saw in this blog series, cacao flavours are unique, complex, and fascinating. There are a multitude of factors that decide the ultimate flavour character. Chemical, biological and physical aspects all have an influence on the composition and the formation of cacao bean flavours, with fermentation playing a key role in the formation of flavour precursors for the development of the final flavour. 

Link to related blogs you may enjoy 

🔶Uncovering The Flavours Of Chocolate Series | The Impact Of Cacao Variety & Genetic

🔶Uncovering The Flavours Of Chocolate Series | The Impact Of Cacao Origin & Terroir 

🔶The Secret Of Cacao | First Steps Towards Chocolate: Harvest & Process

References

Level 2 Certificate in Chocolate tasting https://www.chocolatetastinginstitute.org/ 

Stephen T Beckett, The Science of Chocolate, 3rd Edition, 2018

Alistair Paterson, Mark Fowler, Angela Ryan , Flavor Formation and Character in Cocoa and Chocolate: A Critical Review, 2008 Critical Reviews In Food Science and Nutrition

Ana Clara Aprotosoaie, Simon Vlad Luca, and Anca Miron, Flavor Chemistry of Cocoa and Cocoa
Products—An Overview, Comprehensive Reviews in Food Science and Food Safety  Vol. 15, 2016

Lídia J R Lima, M Helena Almeida, M.J. Robert Nout, Marcel Zwietering, Theobroma cacao L., "The Food of the Gods": Quality Determinants of Commercial Cocoa Beans, with Particular Reference to the Impact of Fermentation, 2011, Critical Reviews In Food Science and Nutrition

Additional resources to go further 

Bob Holmes, Flavour: The science of our most neglected sense

Harold McGee, Nose Dive

Maricel E. Presilla, The New Taste of Chocolate  

Bee Wilson, First bite - how we learn to eat 

Sophie D Coe & Michael D Coe, The True History of Chocolate