How does air exposure impact the freshness of coffee?

Air exposure significantly affects the freshness of coffee, primarily leading to oxidation. When coffee is exposed to air, the oxygen interacts with the coffee's oils and compounds, which can alter its chemical structure. This process can result in the degradation of the flavor and aroma compounds that contribute to the coffee's overall profile. Over time, oxidation causes the coffee to taste stale, flat, or even rancid, as the desirable volatile compounds dissipate while undesirable notes may develop.

The other options suggest benefits of air exposure that are not accurate. While some might think that air could enhance flavors and aromas, it is actually the lack of exposure that retains the coffee's freshness. Preventing oxidation is crucial for maintaining flavor; thus, air exposure contradicts this principle. Lastly, air does not preserve coffee; in fact, it accelerates spoilage, undermining freshness rather than extending it.