How to tell if your green coffee beans are old?

Common denominator: if the beans are brown, they are old. Otherwise it’s hard to tell by looking. Some beans start out greenish and get to a tan color when they are a year or two old; but many others start life tan colored. One cannot assume you have bad beans because of the tan color. Some beans age well in terms of taste; some don’t.

You can tell by the cup. Beans that should have floral and fruity aromas can fade quickly and lose these in a few months. Acidity decreases slowly, and a woody taste can become dominant at lighter roasts. At darker roasts, age doesn’t show up as dramatically. The residual acidity shows up as a slightly juicy quality to the bitter-sweet flavors — think of a cake that’s moist versus one that’s dry — and a faded coffee can lose this.

Coffees can also get spoiled with age by mold, mildew or other microbial action. If the coffee tastes acrid, vinegary, like dried beans or peas, or like cabbage, the beans have taken a hit in processing or storage.