Spitballing from the basic chemistry, freshness is mostly about the time before the beans are rancid, the packaging used will hold in volatiles but oxygen + hea

Spitballing from the basic chemistry, freshness is mostly about the time before the beans are rancid, the packaging used will hold in volatiles but oxygen + heat will make beans unpleasant. I wince a bit when I see coffee in the coop-style dispensers, that's a recipe for unsavory flavors. So date-since-roast is also a proxy for likelihood of rough treatment, and it's lore from a world which includes roasted beans which aren't stored sealed in any way. I have had coffee taste fine a month after roast if stored carefully, and in the tropics, fresh roasted beans can go off on you in a few days, if they live in a kraft paper bag at outdoor temperatures and humidity.