There are many factors that will affect the colour, flavour, and contents of the cacao beans. These include the variety of cacao tree, the location of the tree, soil conditions, and the fermentation process. Fermentation is one of the most important post-harvest processes for cacao beans as this is when the compounds responsible for the flavour of cacao and its brown colour are able to develop^1–4. Without this process, dried cacao beans would be grey in colour, bitter and not possess the characteristic “chocolate” flavour for which it is known⁵. While fermentation reduces the bitterness of the cacao,^3,4 it also increases the presence of important minerals, including calcium and magnesium⁶. Variation in the timing, length, and conditions of fermentation can result in cacao beans with slightly different flavours, chemical composition and colour⁷.

Following the initial harvesting, the cacao pods are broken, and the beans removed, either manually or by machine^1,3,4,7. It is at this point that any beans defective in some way are removed³. The fermentation process then follows in which a select amount of fresh cacao beans are piled and allowed to ferment for several days³. During fermentation, the beans may be turned or transferred to other containers for aeration³. Typical containers for fermentation of cacao beans include wooden boxes, baskets, drying plates, or open heaps³. Fermentation of Forastero and Trinitario varieties can take up to 10 days fermenting³. Our Criollo cacao beans are typically fermented between five and seven days. The beans are stacked in layers in wooden crates and turned at regular intervals throughout the fermentation process.

Fermented and dried raw Criollo cacao beans.

Fresh cacao beans are made up of about 40% seed pulp, which is a combination of spongy tissue and a cell sap, rich in sugars, salts, organic acids, proteins, and pectin, an important component of plant cell walls¹. The traditional fermentation process begins with the microbes naturally present, such as yeasts, bacteria, and fungi¹. These microbes feed on the sugars and organic acids in the cacao bean to produce heat and carbon dioxide gas¹. The temperature of the bean may reach up to 50˚C.¹ Many different chemical reactions occur during the fermentation process which change the components in the cacao beans and lead to the development of their colour, aroma, and flavour¹.

Anthocyanins are compounds that add to the astringency of cacao and are responsible for its dark deep purple-brown colour when raw¹. Polyphenol and flavonoid compounds, such as catechins and procyanidins, are important for the development of the colour and flavour of the cacao during fermentation. These compounds are oxidised causing a reduction in the astringency of the beans and development of the characteristic “chocolate” flavour, as well as a change in colour from deep purple-brown to a “truer” brown^1,5. Polyphenols and flavonoids are important as they are precursors for antioxidant compounds that are protective against cardiovascular diseases, cancer and inflammation².

During fermentation, essential amino acids, antioxidants, and minerals, including magnesium and calcium, are also produced^1,5,6. Caffeic acid aspartate is one antioxidant produced during fermentation that has been found to reduce inflammation in the body and is greatest in Criollo varieties of cacao². Much of the variation in other flavonoids, polyphenols, and other important fermentation precursors between different varieties of cacao is due to differences in the soil quality².

At the end of the fermentation process, the moisture content of the cacao beans is reduced to about 6-8%³. At the end of the fermentation process, the cacao beans are dried between seven days to three weeks, either by sun drying or mechanical means before being cleaned and packaged³. The resulting cacao beans are now ready for processing into various cacao-based products, such as chocolate, cacao powders, cacao pastes, and more. Chocolate manufacturers may roast cacao beans produce cocoa-based products and enhance the chocolate flavours and ensure a more consistent flavour profile throughout an entire batch^1,2,4. However, roasting and other forms of heat treatment can affect the chemical composition of cacao and reduce the presence of beneficial compounds, such as flavonoids and anthocyanins^8,9.