Is it safe to drink old coffee?

Coffee is a shelf-stable product, meaning it is not prone to the same rapid bacterial growth as fresh produce or dairy. As long as your beans or grounds have been kept away from moisture, they are safe to consume even months past their peak freshness. The primary issue with 'old' coffee is not safety, but quality. Coffee is packed with volatile aromatic compounds that give it its signature scent and flavor; these compounds begin to dissipate the moment the beans leave the roaster.

Oxidation is the main culprit behind stale coffee. When coffee is exposed to oxygen, the oils on the surface of the bean begin to degrade, leading to a loss of the bright, complex notes that specialty coffee is known for. If you have ever brewed a cup of coffee that tasted like cardboard or old paper, you have experienced the effects of oxidation. While this is unpleasant, it is entirely harmless from a biological standpoint.

However, there is one major exception to the safety rule: moisture. If coffee is stored in a humid environment, it can develop mold. If you see any visible signs of mold, or if the coffee smells musty or fermented in an unpleasant way, you should discard it immediately. Similarly, if you are using pre-ground coffee that has been sitting in an open container, it may have absorbed odors from your kitchen, which will negatively impact the taste.

In practice, if you find yourself with a bag of coffee that is past its prime, you don't necessarily need to throw it away. While it may not be ideal for a pour-over where you want to highlight delicate flavors, it can still be perfectly acceptable for cold brew or for use in recipes like coffee-rubbed meats or baking. To keep your coffee at its best, always store it in an opaque, airtight container in a cool, dark place, and try to consume it within a few weeks of the roast date.