Coffee freshness is not one date, it is a curve. Beans are too fresh for the first few days, best in the middle of a window, and stale after it. Knowing where you are on that curve changes how you should brew.
The timeline for whole beans
| Days after roast | What is happening | How it brews |
|---|---|---|
| 0 - 3 | Heavy carbon dioxide release | Hard to extract, foam is unstable, espresso gushes |
| 4 - 6 | Degassing slows | Improving, still needs a coarser grind |
| 7 - 21 | Peak aromatic development | Best window for all methods |
| 22 - 42 | Slow oxidation | Good, needs a finer grind or longer contact |
| 43 - 60 | Aromatics fading | Flat, works with milk |
| 60+ | Stale | Papery, woody, no sweetness |
Ground coffee is a different scale
Grinding multiplies surface area by thousands. Ground coffee loses roughly 60% of its aromatic compounds within fifteen minutes of grinding, and is noticeably flat within a week even in a sealed bag.
This is the entire argument for grinding at home. A 200 dollar grinder with mediocre beans beats excellent beans ground a week ago.
What speeds up staling
Four things, in order of impact: oxygen, moisture, heat and light. A bag rolled shut and left in a warm cupboard is the classic mistake. A one-way valve bag, squeezed to remove air, in a cool dark place is the practical answer.
The fridge is worse than the cupboard. Every time you open the door, the bag meets warm humid air, then cools again, and condensation forms inside.
Does the freezer work?
Yes, with conditions. Freeze in an airtight container with as little air as possible, in portions you will use at once, and grind straight from frozen. Beans are stable frozen for several months.
The failure mode is repeated thawing. Each cycle condenses moisture on the beans and degrades them faster than leaving them out would have.
Roast level changes the window
Dark roasts degas faster and go flat sooner, so their window is roughly 7 to 28 days. Light roasts hold up longer, 14 to 45 days, and sometimes need a week before they taste their best.
How to tell where you are without a date
Chew a bean. Fresh beans are crunchy and aromatic; stale beans are soft, hollow and taste like cardboard. That test is more reliable than any printed date.