Coffee doesn’t spoil in the way milk spoils. Old coffee won’t make you ill. It just stops being interesting, and it does that much faster than the packaging suggests.
Two things are happening. The gas that roasting puts into the beans escapes, taking the aroma with it. And the oils that carry most of the flavor slowly go rancid, which is what stale coffee actually tastes of — flat, papery, faintly like cardboard.
How long you actually have
Whole beans:best from about three days to a month after roasting. They’re still perfectly drinkable for two or three months; they just get progressively duller.
Ground coffee:a week or two, and that’s generous. Grinding multiplies the surface area enormously, so everything that was going to escape escapes far faster. This is the single strongest argument for owning a grinder, and we make it at greater length elsewhere.
Brewed coffee:about thirty minutes at its best, and then it’s a hot brown drink. On a warming plate it turns properly nasty in under an hour.
The date that matters is the roastdate. A best-before a year out tells you nothing except that the roaster would rather you didn’t think about this.
Where to keep it
Somewhere sealed, dark and room temperature. A cupboard is fine. The bag it came in is usually fine, if it has a one-way valve and you roll it down. An airtight tin is slightly better. That’s the entire equipment list.
The enemies are air, light, heat and moisture, in roughly that order. Which brings us to the two places everybody keeps coffee.
Not the fridge
A fridge is humid, and it’s full of food. Coffee is porous and takes on smells with real enthusiasm. Every time you take the bag out, moisture condenses on cold beans and then goes back in with them.
If your coffee has ever tasted vaguely of onion, this is why, and we are sorry to be the ones to tell you.
The freezer, with conditions
The freezer genuinely works, but only if you commit. Portion the beans into small airtight bags first, freeze once, and take out one portion at a time, grinding straight from frozen. Never refreeze, and never open the main bag while it’s cold.
Freezing and thawing the same bag repeatedly is worse than just leaving it in the cupboard. If you’re going to drink it within a month anyway — and you probably are — don’t bother.
The honest advice
Buy less coffee more often. A small bag you finish in three weeks beats a large one you’re still working through in June, and given what coffee costs now, the bulk bag stops being a saving the moment half of it goes flat.
We wrote about learning this the expensive way back in 2016.