Post-Harvest Process: The Vital Role Fermentation & Drying Play in Cacao’s Flavour
- marco097307
- 5 days ago
- 3 min read

Why the Post-Harvest Process (Fermentation & Drying) Is Key to High-Quality Cacao
Most people don’t realize it, but one of the most important steps in producing high-quality cacao happens after the pods are harvested. It’s called the post-harvest process which consists of fermentation and drying of the cacao beans. Without it, cacao beans wouldn’t develop the unique aromas, flavours, and properties that make them so valuable.

What Happens during the Post-harvest Process?
The first step is fermentation.
Once the ripe cacao pods are opened, the beans and their mucilage (the citric, sweet white pulp around the beans) are placed into wooden boxes for several days. During this time, the natural yeasts and bacteria in the air trigger chemical reactions in two stages.
The first stage is called the anaerobic stage (yeast stage), where the wild yeasts begin metabolizing the sugars in the cacao pulp, producing ethanol (alcohol) and heat.
Then comes the second stage, the aerobic stage (bacterial stage), where acetic acid bacteria (acetobacter) convert the ethanol into acetic acid.
This raises the temperature even more, triggers chemical changes inside the bean, and starts the transformation of flavour precursors. This is when raw cacao begins to develop its true identity. Without fermentation, cacao would be astringent, bitter, and soapy— not rich and complex in aromas and flavours.
The second step of the post-harvest process is drying. And it’s just as important. In a well-executed post-harvest process, the tapered end of fermentation is actually finalized during drying, making drying a balancing act of allowing the acetic acid (that vinegary smell and taste) to escape the bean and then locking in the flavour that fermentation started.

Why Fermentation Matters
Fermentation is what transforms raw cacao seeds into flavour-rich cacao beans. Simply put, it creates flavour.
1. It transforms the seed
Cacao beans are actually seeds. Fermentation kills the germ (embryo) inside, which prevents sprouting and triggers internal chemical and microbial activity — an essential step for preserving quality.
2. It brings out flavour potential
Fermentation creates the conditions needed to form flavour precursors inside the bean, as well as inject the flavours of the pulp into the bean. These compounds don’t taste like much at first, but they lay the foundation for the unique aroma and character that fine-flavour cacao is known for.
3. It softens astringency
Raw cacao is naturally astringent due to the natural tannins it contains. Fermentation (during the aerobic stage, to be exact) helps reduce that astringency by breaking down tannin compounds, making the beans smoother and better balanced. Bitterness is a flavour profile often associated with tannins, thus reduction of tannins may also result in a reduction of bitterness.
4. It changes the colour
Fermented beans go from a violet or purple tone to a brown hue. This isn’t just about looks — it’s one of the signs that the bean is fermenting properly.

Why Drying Matters
Drying stops fermentation, stabilizes the bean, and locks in flavour. Simply put, it preserves flavour. 1. Stops fermentation at the right moment
Even, steady, and well-timed drying allows the last bit of acetic acid to escape the bean and stops any further fermentation which can lead to spoiling.
2. Controls acidity and astringency and prevents mold
Drying too quickly: seals the cacao shell’s pours shut, trapping in acetic acid, leading to a vinegary taste.
Drying too slowly: can result in too much moisture, leading to sour beans and runs the risk of mold.
3. Concentrates and stabilizes flavours
Drying helps the beans finish oxidizing and deepening in colour and aroma.
Post-Harvest Process in Summary
Overall, a well-executed post-harvest process helps transform and stabilize the cacao bean’s unique aromas and flavours. Whether the cacao will be roasted for chocolate, pressed into butter and powder, or used in another form, it helps prepare the bean for further processing. Without this vital process, the quality of the final product would be unmistakably compromised.

Tradition Meets Purpose
At Cacao Life, we work closely with Peruvian farmers and cooperatives to ensure the post-harvest process is done right, respecting local traditions while sharing knowledge that helps improve these practices where possible. By focusing on this essential stage, we help preserve the integrity of the cacao and support the people and ecosystems that make it all possible.
So, the next time you see premium cacao, remember: behind each bean lies a process rooted in nature, science, and generations of care.
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