Specialty coffee · Worth knowing

Anaerobic fermentation in specialty coffee is defined by closed vessels rather than the absence of oxygen, since all fermentation becomes anaerobic within hours anyway. According to Felipe Sardi of La Palma & El Tucán, flavor develops through microbial succession—yeasts produce alcohols first, then lactic acid bacteria take over as pH drops, with esters forming throughout and continuing into the drying phase. Raw material quality, temperature, and precise measurement of pH, redox potential, and conductivity matter far more than fermentation time alone, with producers using data to determine when to end fermentation rather than following predetermined hours. Balancing anaerobic processing with terroir requires producers to decide how intensely the technique should express itself. Sardi argues that maximum intensity shouldn't be the goal if it obscures the variety or origin character—his farm tests whether they can still distinguish a Geisha from a Sidra after processing, keeping experimental lots separate from terroir-focused ones. Anaerobically fermented coffees are more fragile than conventional lots during storage, requiring careful attention to water activity, hermetic packaging, and temperature control, since the volatile esters that justify the premium are the first compounds to degrade when exposed to oxygen, heat, or moisture.

Jose Posada's Capilla del Rosario farm in Antioquia, Colombia demonstrates advanced processing innovation through cofermented washed technique. The lot uses a natural chocolate broth fermentation method combining cocoa powder, cane-derived sugars and microbial cultures to enhance body, acidity and chocolate character without artificial additives. Posada, a fourth-generation grower with background in business and culinary arts, has transformed the 45-hectare farm into a recognized hub for processing experimentation, operating full on-site infrastructure including fermentation tanks, sensory lab and sample roastery while hosting educational sessions on cupping and harvest techniques.

The Fermentation Project is a curated tasting experience featuring four distinct Guatemalan coffees processed using different fermentation approaches: a mechanically washed control, wild fermentation with local microbes, Lactobacillus inoculation, and yeast inoculation. Each method is designed to showcase how fermentation impacts flavor complexity, brightness, body, and aroma, with participants able to taste alongside James Hoffmann during a live cupping session as he shares his insights on each coffee. Lucia Solis, a fermentation and processing specialist with over 12 years of international experience across 15+ countries, serves as the project's consultant. She studied viticulture and enology at UC Davis before transitioning from nine years in wine production to coffee fermentation work, and now helps producers apply microbiological principles to develop reproducible cup profiles while bringing stability and operational control to the fermentation and drying stages of coffee production.