What is the impact of over-extraction on coffee?

Over-extraction occurs when coffee is brewed for too long or with too finely ground coffee, causing more soluble compounds to be dissolved into the brew than intended. This process can lead to the extraction of undesirable compounds such as tannins and excessive caffeine, which contribute to bitter and astringent flavors. The taste profile of over-extracted coffee generally becomes unpleasant, overshadowing any sweeter or more nuanced flavor notes that might have been present otherwise.

The incorrect options reflect desirable outcomes that do not occur with over-extraction. For example, enhancing sweetness or achieving a perfect balance of flavors implies a well-timed and appropriate extraction process, which over-extraction fails to deliver. Similarly, while aromatic compounds are important in coffee, over-extraction typically results in an uninviting aroma dominated by bitterness rather than the more pleasant fragrances that come with properly extracted coffee.