What Really Happens During Cocoa Fermentation?

Cocoa fermentation is a fascinating and complex process that has a profound impact on the development of chocolate’s flavour, aroma, colour, and texture. Interestingly, while we refer to the process as fermenting the cocoa, it’s actually the yeast and bacteria in the pulp surrounding the cocoa beans that undergoes fermentation, not the cocoa bean itself. Yeast and bacteria get into the pulp once farmers crack the cocoa pods open to begin transforming them into chocolate. Get the full details of what really happens during cocoa fermentation below.

The Anaerobic Phase

We derive chocolate from the seeds of the cocoa tree. Once farmers harvest the cocoa pods, they open the pods and extract the seeds (the cocoa beans) covered in slimy white pulp (mucilage, or baba). Farmers place the cocoa seeds and pulp into large wooden boxes or piles and cover them with banana leaves. The leaves contain enzymes which activate the naturally occurring yeast and bacteria in the pulp and on the surface of the bean to create an anaerobic (oxygen-free) environment, which is necessary for the first fermentation phase. 

During this phase, yeast, bacteria, and other microorganisms begin breaking down the sugars in the pulp, producing ethanol and carbon dioxide. The bacteria that produce lactic acid also break down the carbohydrates found within the pulp. 

As the cocoa pulp breaks down, it gradually becomes a liquid in a process known as “sweating.” The liquid mixture contains sugars, acids, and enzymes that contribute to chocolate’s unique flavour and colour. This breakdown also allows oxygen to enter the pulp, kicking off the second fermentation phase.

The Aerobic Phase

Things start heating up at this stage! Yeast and bacteria multiply rapidly, consuming oxygen and producing heat as a byproduct. The microorganisms break down the ethanol and acids produced during the anaerobic stage to create energy. The rising temperature creates an ideal environment for the yeast and bacteria to thrive.  

After five to ten days, the pulp’s colour darkens and the key aromas develop; the fruity, sweet smell of raw cocoa beans slowly transforms into the familiar chocolate scent we all know and love, and contributes to the development of the desired rich, brown colour associated with chocolate.

During this stage, the pulp also becomes more acidic, which is important for developing the chocolate’s flavour.


After fermentation is complete, farmers spread the mixture out in the sun and air to dry. The drying stage stops fermentation and allows the beans to become uniformly dry to prepare them for bagging and shipping to manufacturers.

Why Fermentation Matters

Fermentation plays a crucial role in the production of quality chocolate. The duration of fermentation impacts the final flavour of the chocolate—too short, and the chocolate may be acidic and raw-flavoured, too long, and it may become overly mellow and lose some characteristic chocolatey notes.

After fermentation, the cocoa beans undergo additional processing steps such as drying, roasting, grinding, and conching to transform them into chocolate products. The flavour development achieved during fermentation sets the foundation for the rich, complex taste that is characteristic of high-quality chocolate.

Order Couverture Chocolate

Cococo is an online chocolate shop that has many collections of delicious, couverture chocolates. We have tasty options such as chocolate-covered snacks, chocolate gift boxes, and vegan-friendly options. Treat yourself or someone special to our premium chocolate today!