Post by Allie Collopy
Of all the many stages in producing a quality cup of coffee, fermentation may be one of the more lesser known processes. Growing and harvesting coffee cherries on the foothills of lush volcanoes is undeniably idyllic and even non-coffee drinkers appreciate the aroma of coffee roasting, but there’s another step in taking the coffee from seed to cup which has a dramatic impact on the finished product. Let us turn our gaze to the unsung hero of fermentation!
Fermentation is performed after the coffee cherries have had their pulp removed and before the beans are washed and then left out to dry in the sun. De-pulped coffee beans need to ferment for 36 hours to ensure the honey that surrounds the coffee beans is completely dissolved. Just as with winemaking, fermentation occurs when coffee’s natural yeast and bacteria interact to break down sugars and convert them to acids, which affects the smell and flavor profile of the beans.
Despite being an integral component of coffee production, fermentation can be hard to regulate and small environmental changes will have impacts on the final product. Fermenting at lower temperatures will allow for more pronounced acidity, whereas higher temperatures can create more sweetness. Producers also have to decide if they will ferment with rainwater or spring water, which can influence the flavor profile. If they prefer a wet or dry fermentation, which is more standard in some regions than others. If the beans are left to ferment for too long, the alcohol acids can overpower an otherwise quality harvest and negatively impact how the coffee cups. Exercising precision, intention, and control during the fermentation of coffee, just as with the fermentation of beer and wine, is essential to maintaining consistency in the finished product.
One of our partners, Ija’tz, has used a unique method of fermentation where de-pulped beans are put into shallow canals, left to ferment, and then washed in the same location a day and a half later. While the cooperative produces high-quality specialty coffee, this nontraditional approach makes it hard to control the quality and rate of fermentation, which was resulting in some uneven batches.
The Ija’tz cooperative was established in 1998 in San Lucas Tolimán on the shores of Lake Atitlán. The name Ija’tz comes from the Kaqchikel word for “seed,” as the co-op is comprised mainly of indigenous Maya Kaqchikel-Tz’utuhil families who are motivated by keeping tradition alive, preserving native Guatemalan plants, providing for their community, and of course, producing a great cup of coffee.
After reviewing practices in their wet-milling process, Ija’tz requested support in building two fermentation tanks on site, so that quality may be more readily controlled and the production process can move more quickly. Each tank will be able to hold an impressive 40 quintales of de-pulped coffee, which will then feed into the channels for the coffee to be washed.
And so, with generous funding from Joe Van Gogh roasters, who purchase Ija’tz coffee, and the support of a service learning group from University of Wisconsin Eau Claire, a group of 13 descended upon co-op and construction began! Students broke off into groups to mix cement, stack cinder blocks, and snake rebar through the structure to provide additional stability. At the end of two days, the co-op was left with two new tanks, just in time to finish processing the 2018 harvest.