Many Aequitas farmers are participating in a fermentation project called Artisans, sponsored by NuCoffee, an unconventional buyer who trades coffee for agricultural inputs. Farmers sell them commercial coffees to finance their farm inputs. In addition to the coffee, NuCoffee gets data – farmers are given bonuses for submitting details on farm management. This year NuCoffee is trialing a program to encourage experimentation in anaerobic fermentation.
Farmers were supplied with 10L of yeast – the same yeast, so as to act as a control. They were also given an overview on fermentation and training (via zoom) by a federal university. Farmers were then asked to buy the barrels and contribute 10 bags of coffee to the experiment; 9 of which they could sell themselves, 1 of which could go back to the university for evaluation. The Aequitas team heard from the Artisans technical assistant that Nucoffee cupped a dozen of these experiments from members, and found some of the lower-scoring lots (below 80) improved on score (to 83, for example) with a different profile (more, and more complex fruits). However, among Aequitas partner producers where coffees come in 83 and above normally saw little change from their controls (those which did not undergo fermentation). As with many fermentation experiments, the results were inconclusive. It tended to teach that fermentation can bring up the bottom of a bad tasting coffee but isn’t as impactful on raising the ceiling for those which are already scoring well. Over 400 producers participated and results are expected to be shared prior to next year’s harvest.
Independently, Yuki and some of her colleagues decided to have their own fun with fruity fermentation. That’s literally combining coffee cherry with macerated fruit for 48 hours of anaerobic fermentation.
1-Flavor mapping was used to identify areas that produce higher quality coffees.
2-These areas were scheduled for hand-picking instead of mechanical harvest.
3-Cherries were floated to remove debris and lighter beans.
4-Cherries were then soaked in cold water (15C, anaerobic) for 48 hours.
5-After 48 hours, next came the fruit mixture: intensively prepared by slicing fruit, blending, and adding a little water. This they did with two different concoctions (which were in turn put next to a control).
– Citrus: 50KG of lemon-orange fruit mix put across 10 barrels (5KG per barrel, each of which contains 200L of coffee).
– Pineapple: 30 KG of pineapple pulp put across 5 barrel, (6KG per200L of coffee cherry)
– A control was established using 5 barrels of the same coffee, undergoing the same process except without the fruit mixtures.
6- After 72 hours they opened the barrels, cherries were then placed on raised beds and they washed the coffee with a water solution used in food sanitization to stop the fermentation process.
7-Cherries were then left to dry as a natural. First round, full sun, two weeks. Second round, partial shade, 30 days.
It’s a lot of fruit, a lot of work. And it burned out a blender. But the results were fun on the tongue. The citrus batch gave off big spicy lemon-mint gingerbread aromatics which held through in the cup, and cooled tropical. The pineapple experiment tasted like, surprise, pineapple wine with watermelon / green apple schnapps on the aroma, a sweet brown bread body, and some mint on the finish.
Lot are listed on offers, but have not yet been milled – so availability for this year is uncertain. However, experiments will be replicated in the off-season so that they are ready to scale come next harvest.