What is one effect of using paper bags for coffee storage?

Using paper bags for coffee storage has a notable effect regarding oxidation, primarily because paper is permeable to oxygen. When coffee is stored in a paper bag, it does not provide a barrier against oxygen, which can lead to increased oxidation of the coffee beans. Oxidation causes the flavors to deteriorate over time, leading to stale or off flavors in the coffee.

In contrast, options that mention moisture retention or preservation of flavor are not accurate, as paper bags do not effectively protect against moisture either; they can absorb moisture, potentially compromising the coffee beans further. Additionally, metal cans, while they may preserve flavor better compared to paper bags, are not related to this specific context. Therefore, the characteristic of paper bags allowing greater exposure to oxygen and consequently increasing oxidation aligns with the effects observed in coffee storage.