What effect does the age of ground coffee have on extraction?

The age of ground coffee significantly affects extraction primarily because of the chemical changes that occur over time. As coffee beans age after they have been ground, they begin to lose their freshness due to oxidation and the evaporation of volatile compounds that contribute to flavor and aroma. This degradation can result in uneven extraction during brewing processes, as the quality of the coffee particles is inconsistent.

Older ground coffee may exhibit stale or diminished flavors, which can affect the overall balance and complexity of the brew. When brewed, the less flavorful particles may extract differently compared to the fresher particles, leading to an uneven cup with some flavors being overly pronounced while others are subdued. Thus, the age of ground coffee directly impacts the extraction quality, leading to a combination of loss of flavor and varying extraction across the batch. This highlights the importance of using freshly ground coffee to ensure a more uniform and flavorful cup.