Recently we had the chance to welcome to London Dionathan Almeida, World Cup Tasting Champ 2025, when he visited us with SMC, a speciality coffee company we work closely with in Brazil.
We are lucky enough to have a few champs and ex-champs amongst our network as well as producers that grow the coffee for them too. What makes Dionathan special though is that he performs both roles. As the person in charge of a lot of the processing at Aracaçu in Brazil, as well as roasting the samples and for their on-farm tourist café on a larger roaster, he is perhaps uniquely positioned to understand the minutiae around coffee drying and roasting that many of us cannot.
We sat down with him on his recent trip to London to chat through this detail.
What’s the premise behind all of this, where do we start?
Well-executed drying during post-harvest allows the bean’s full sensory potential to be easily unlocked during roasting. At harvest, ripe coffee cherries typically have a moisture content of around 50–60%. During the coffee drying process, moisture is gradually reduced until it reaches a final level of 10 to 12%. During coffee roasting, the water inside the bean is removed primarily through evaporation and mechanical expulsion caused by rising internal pressure. This process unfolds in stages as the temperature increases, reducing moisture to between 1% and 3% by the end of roasting.
Ok. So far so good. But it’s not just about removing moisture.
No. The first drying stage the goal is to remove surface water from the beans, which accumulates during separation, washing, and pulping at the wet mill. Initially, the coffee is spread in a thin, single-layer on the drying patio to promote quick moisture evaporation. At this stage of the drying curve, the sun is the most effective and natural ally.
After the initial drying phase, it’s important to protect the coffee from excessive heat.
At this stage, the lot is gathered into thicker layers to reduce sun exposure. Solar radiation remains a valuable ally, but the coffee must be regularly turned to ensure even drying by rotating the layers exposed to the sun.
As the beans lose moisture, they become more exposed and sensitive to temperature. Monitoring heat exposure is crucial to preserve the beans’ physical and chemical integrity. Temperatures above 40°C within the coffee mass can lead to cell death and uneven drying.
And as we know, uneven drying leads to lower cup quality overall. So is it just these two drying stages?
When coffee reaches a moisture level between 17% and 16%, resting becomes essential. This third stage allows internal moisture to migrate toward the bean’s surface. During rest, beans exchange energy, enabling the lot’s humidity to stabilize and become uniform.
Research by Professor Flávio Borém shows that processing and drying methods—especially in natural coffees—directly influence the release of volatile compounds. Post-harvest processing affects the bean’s chemical composition and, consequently, its sensory quality. Natural coffees, dried with the fruit skin intact, may undergo fermentation that alters gas and volatile compound formation, setting them apart from wet-processed coffees.
The final, fourth stage of drying, after the resting period, should be carried out slowly and ideally under mild temperatures.
As mentioned earlier, the drier the coffee becomes, the more sensitive it is to high temperatures. In this image to the left, the ‘volcano’ method is shown — a technique that promotes slow drying by reducing the beans’ exposure to direct sunlight.
That shows that not all drying is the same! Do you have any ‘personality’ in the processing that you think adds to its uniqueness?
At Caxambu and Aracaçu farms, all coffees rest for a minimum of 20 days after drying. Beyond the technical benefits, we see this pause as a gesture of respect for the beans — still alive, having gone through so many stages from harvest to processing, and deserving care until they reach the roast.
The resting period after drying allows the lot’s moisture to stabilize through internal redistribution within the coffee mass. This stage also helps reduce excess freshness, an undesirable herbal flavor reminiscent of coffee leaves, improving the overall sensory experience.
And for those of us lucky enough to have visited the farm, we know there is a special treat there too! Perhaps we’ll keep that a semi secret for those who will visit in the future.
So how do these relate to roasting then? Is dried coffee just that, or do you see another connection?
Post-harvest practices are deeply connected to the roasting process and have a direct impact on how it is carried out, and ultimately, on the final result.
In every step of post-harvest handling, our priority is to protect the life of the bean, preserving its physical and chemical structure while ensuring uniform moisture content. We believe that balance among these factors leads to quality, consistency, and extended shelf life for our coffees.
The way moisture is sometimes read doesn’t tell us the full story. As a single reading, it could be a large number of beans as a particular percentage or an average of a wider spread. That wider spread will perform less evenly then.
Yes, here are two charts that show exactly that.
Moisture in both samples is very close, but the spread in the upper profile is much wider, importantly including beans that should be rejected at both ends of the scale. This is from a batch which has not been dried so well.
The bottom batch has a much narrower spread, showcasing better controls, and importantly, has nothing outside either parameter.
Beans with uneven moisture content or damaged physical and chemical structures will react inconsistently during roasting.
As a result, the heat inside the roaster affects each bean differently, leading to an uneven roast and preventing the full expression of the coffee’s quality potential.
So by carefully controlling each batch on the patio, you can better understand the properties of the bean and adjust your roasting style to fit exactly what you need. Combine this with the individual thermal properties of concrete and brick patios for example, or raised beds and specific geographical / topographical sitings then it’s easy to see how much of drying is overlooked or not understood properly. Sounds like a great reason to come on an origin trip to learn more!
Jamie and Hannah will be visiting SMC and Dionathan at Aracaçu again later this year. Get in touch if you would like to join them!
