The State of the Art in Coffee Fermentation

/ / Business, Food & Flavor

More specialty coffee producers are developing unique approaches to their coffee bean fermentation, isolating native microorganisms to create a flavorful cup or  working closely with rural farmers to utilize fermentation control techniques on small-scale operations.

“Practically all the coffee we drink has been fermented in one way or another. But there is huge room for improvement, innovation and development in the realm of coffee fermentation,” says Mario Fernández, PhD, Technical Officer with the Specialty Coffee Association (SCA). The SCA partnered with The Fermentation Association for the webinar The State of the Art in Coffee Fermentation

Fernández continues: “Coffee is produced by millions of small coffee producers around the tropics that have very little capital to invest in fermentation equipment. Oftentimes, the price is too low for them to add fermentation controls as part of the cost equation. Therefore, for perhaps 99.9% of coffee in the world, it undergoes wild fermentation, in which the microbes grow on the mass of mucilage in a wild fashion and the coffee producer only controls certain parameters, such as the length of the fermentation.” 

Two industry experts on the forefront of coffee fermentation technique and technology joined Fernández — Felipe Ospina, CEO of Colors of Nature Group (multinational specialty coffee trader) and Rubén Sorto, CEO of BioFortune Group (a coffee, upcycled and food ingredient manufacturer based in Honduras). 

Post Harvest Processing Technology

Sorto is adapting fermentation technology to coffee, mapping the microbiota of the bacteria and yeasts that are present at Biofortune Group’s farms.

“We realized that fermentation was one of the key aspects of the coffee production that hadn’t been addressed,” Sorto said, noting fermentation is controlled in industries like dairy, wine, beer and bread but not in coffee. “We learned that our soil, our water, our coffee trees, our leaves, our [coffee] cherries, had a large compendium of bacteria and yeast that were involved in the posterior fermentation process…some of the yeasts and bacteria were definitely beneficial and were urgently needed during the fermentation but some of them were not.”

To maximize flavor, they focus on that complex array of bacteria and yeasts, preferably indigenous to the countries of origin. These microorganisms thrive in their local environment, reflecting altitude and temperature. To control the fermentation of those bacteria and yeasts, Biofortune reduces the variables, including monitoring pH levels, alcohol content and container contaminants.

“If you are able to control the fermentation, you are also able to offer a higher-quality product, a consistent quality product…and that’s what the market is looking for, consistent quality in a cup,” Sorto says.

Educating Coffee Farmers

Ospina, meanwhile, is researching fermentation techniques accessible to small-holder coffee producers and training them. The goal is for them to understand the role of each microorganism, discover how to use it in fermentation, then scale that knowledge to small-scale operations, so they can produce incredible coffees. 

At La Cereza Research Center, the Colors of Nature facility in southern Colombia, they are experimenting with fermentation processes. Some alcoholic fermentations result in coffees that produce coffees that taste of whiskey, cognac, champagne, sangria or even beer. Lactic fermentations might produce coffees with flavors of banana, mango, papaya, grapefruit or even cacao. “This is showing us the potential is humongous,” Ospina says.

“Wild fermentation is the ultimate expression of the terroir and it’s very important for us because the terroir produces unique coffees,” Ospina says. “The thing is, we don’t understand wild fermentation yet, but I’m very against demonizing wild fermentation. Why? Because we have seen hundreds and hundreds of outstanding, amazing coffees from all over the world that have been produced with wild fermentation.”

There are challenges. Food safety is a big concern. Ospina teaches the use of disposable gloves at the farm level to prevent contaminants, and to put a new plastic bag in the bioreactor for each batch of beans to avoid cross-contamination. 

The cost of implementing fermentation technology can be high. Sorto recommends to start by buying each farmer a pocket pH meter and a refractometer to closely monitor the fermentation.

“Translating science and technology to small farmers with very little investment will help them increase the possibility of a higher income because if you are not able to control fermentation, you are risking the effort of a one year harvest,” Sorto advises.