That fermentation affects flavor is a widely accepted concept, buthow exactly this happens is still a little unclear.
Again, we at Cafe Imports aren’t flavor scientists, just flavor hunters: We know from what our producing partners tell us that fermentation is a primary part of what they do in order to make a living off quality coffee, and we know from our tasting experience and expertise that coffees’ flavor will vary from year to year, place to place, process to process—even if the producer says they follow the identical steps.
Producers use various tools and methods for tracking the progress of their fermentation, including using Brix meters to get a general reading of sugar-soluble content in coffee fruit as it’s ripening on the trees, and later as it’s being fermented (sugar content will go down as microorganisms metabolize it). Degrees Brix (°Bx) is a measurement of sugar solubles, specifically sucrose, in a water-based solution—which is what most fruit basically is, sugar suspended in water. In wine, Brix readings are used to determine optimal fermentation and flavor production in processing and to prevent bad or off fermentation, but it’s important to remember that the grapes themselves are what become the finished, altered product. For this and other reasons, °Bx is not a purely accurate measurement for coffee ripeness (or fruit ripeness in general), since it will vary based on concentration within the fruit—including changes caused by environmental factors such as rainfall, or even throughout the course of the day with modulations in sunlight, temperature, even Earth’s position relative to the moon. (No, really.)
What’s more, there are sugars other than sucrose present in the coffee fruit, in addition to other compounds like acids and the alkaloid caffeine. Taking a single reading to determine ripeness, then, will not necessarily always yield the best results: The effectiveness is in comparison, contrast, context, constant and consistent record-keeping, and critical thinking.
