What is The Fermentation Project?

Two personalities well known in the world of specialty coffee, Lucia Solis and James Hoffmann, have teamed up to create the Fermentation Project and reached out to roasters around the world to collectively compare how four different types of fermentation in coffee make a coffee taste different.

The coffee from Finca San Miguel Urias, the farm Lucia and Nick Solis manage in Guatemala, was processed mostly the same overall – but fermented four different ways. The green coffee was then distributed to roasters around the world, including us here at Drip, as part of a global project designed to bring these different fermentation approaches to as many coffee drinkers as possible.

Dispatching Schedule

This is a tasting set of 4 x 80 grams of coffee. We roast and ship the sets in a few batches, with an order deadline for each batch. Pre-orders are collected and all orders placed are shipped with the next batch – not immediately. May sell out before the deadline. Subject to availability and changes.

1st batch: deadline Sep 8 (or when sold out), roasted Sep 9, shipped Sep 10
2nd batch: deadline Sep 22 (or when sold out), roasted Sep 23, shipped Sep 24

Additional batches might be added if any stock will be left after the first two batches.

About the Coffee

All lots are mostly of the Caturra varietal, with some H1 and Bourbon inside. Each of these coffees is what's considered a washed coffee: The coffee cherries are floated when they arrive at the wet mill to sort out defects, pulped, and put into fermentation tanks submerged in water. All of them are fermented for approximately 48 hours – except for the mechanically demucilaged coffee that wasn't fermented. Next, they are washed or rinsed, before being sent to the patios where they are dried for 10–14 days with intermittent shade use to control temperatures.

The Fermentation

This tasting set's four lots each showcase a different fermentation method. Fermentation breaks down the mucilage, but it also affects what a coffee tastes like. The set is designed to be cupped together, each coffee side by side, exploring the question: How does fermentation actually shape a coffee's flavor profile? The following only describes, for each lot, the fermentation step, which is part of the post-harvest processing.

Mechanically Demucilaged

The mucilage – the sticky outer layer around the coffee seed – is stripped away using water and mechanical friction, via a specialized piece of equipment called a demucilaginator, or sometimes referred to as an Eco-Pulper. Many or most producers do not have this machine at their disposal. It makes it possible to process coffee without any fermentation taking place. Coffee processed using this machine is often referred to as semi-washed. This method is considered the control in this project.

Wild Fermentation

The coffee is submerged in a tank of water, where mucilage breakdown happens naturally through the wild microorganisms already present in the surrounding environment. No cultures are added. Because microbial populations shift with location, season, and even the specific wet mill, this method captures a kind of fermentation fingerprint unique to that place and moment, one that's inherently difficult to replicate exactly.

Lactobacillus Inoculated

Mucilage breakdown is driven by a specific dose of Lactobacillus bacteria added directly to the fermentation tank – a more designed fermentation so to speak. Using a specific, known strain, this method aims for a more consistent and predictable fermentation outcome, one that can be reproduced more reliably across batches.

Yeast Inoculated

Mucilage breakdown here is driven by a concentrated dose of yeast added directly into the fermentation tank. Similar to Lactobacillus Inoculated fermentation, but adding yeast instead of bacteria. The two methods have in common that both rely on a more designed fermentation instead of a spontaneous fermentation with the naturally occurring microbes.

About the Project

In the video below, James Hoffmann and Lucia Solis talk about fermentation in coffee and the different types of fermentation applied to the separate lots that are part of this project. A dedicated project site will be launched soon as well.

A global live tasting event will take place on October 3rd, 15:00 UK time (16:00 Swiss time). You will find all the information about this on the project website soon.