Roast date

Roast date is the day coffee beans were actually roasted, and reputable roasters print it directly on the bag because it is the single best indicator of freshness. Most coffee tastes its best somewhere between about one and four weeks after roasting, once initial off-gassing has settled but before the more delicate flavors start to fade.

A best-by or expiration date printed by a large roaster often reflects a much longer shelf life than what actually tastes good, sometimes a year or more out, so it is a poor substitute for knowing the real roast date. Coffee does not spoil the way food does, but it does gradually lose the brighter and more distinct flavors that made it interesting.

When buying beans, look specifically for a roast date rather than a packaged or best-by date, and try to buy amounts you will use within a few weeks. Proper storage in an airtight container away from light, heat, and moisture slows this fading. A common mistake is stockpiling months of beans, which guarantees much of it will taste flat by the time it is brewed.