What are the two biggest enemies of coffee that affect freshness and taste?

The correct choice highlights that moisture and air are indeed the two biggest enemies of coffee that significantly impact its freshness and taste.

When coffee beans are exposed to moisture, they can absorb water, which leads to a quicker deterioration of flavor and aroma compounds. Coffee is hygroscopic, meaning it tends to attract moisture from the environment. This can create an environment that encourages mold growth and results in stale or off-tasting coffee.

Air, on the other hand, contains oxygen, which can cause oxidation of the coffee oils and flavor compounds. Oxidation leads to a loss of freshness and vibrancy in coffee, making it taste flat or stale over time. Coffee beans are best stored in airtight containers to minimize their exposure to both moisture and air, which helps preserve their quality and taste for a longer period.

While light and heat do play roles in coffee deterioration, especially heat, they are not as directly impactful as moisture and air. Sugar and salt do not affect coffee freshness in the same way; rather, they can alter flavor profiles when added but do not contribute to the staleness of the beans themselves. Cold temperatures can actually prolong the life of coffee if stored properly, particularly in the form of beans that are ground and brewed under ideal conditions.