What is over-extraction in coffee brewing?

Over-extraction in coffee brewing refers to the process where coffee grounds are brewed for too long. When coffee is brewed beyond the optimal time, it can result in undesirable flavors being released from the coffee grounds. The extraction of flavors needs to be balanced; while some compounds provide richness and sweetness, others can lead to bitterness and astringency when over-extracted. Optimal extraction typically occurs within a specific timeframe, and exceeding this duration can alter the taste profile negatively. This makes brewing time a critical factor in achieving a well-balanced cup of coffee, which is why it is key to monitor the brewing duration carefully.

The other options present different factors that affect brewing but do not directly correlate with the definition of over-extraction. For instance, using too high of a brewing temperature can lead to extraction issues, but it is a different aspect of the brewing effectiveness. Roasting the beans too dark impacts flavor but does not relate directly to the extraction process, and grinding too coarsely affects the surface area but is not tied to the length of time the coffee brews.