The simple answer
Keep coffee sealed, cool, dry, and out of direct light. Buy an amount you can finish while it still tastes lively, and grind immediately before brewing when possible.
Use the original bag when it works
Many coffee bags have a good zipper and a one-way valve. Press out excess air, close the zipper fully, and store the bag in a cupboard away from the oven or a sunny window.
An opaque airtight container is useful when the original bag does not reseal well. Clear jars look attractive but expose coffee to light.
Should coffee go in the refrigerator?
Usually no. Refrigerators contain moisture and strong food aromas, and the container is opened repeatedly.
Freezing coffee
Freezing can preserve coffee you will not use soon:
- Divide the beans into small airtight portions.
- Freeze each portion once.
- Let a sealed portion reach room temperature before opening it, which reduces condensation on the beans.
- Do not repeatedly thaw and refreeze the same container.
Buy whole beans when you can
Grinding greatly increases surface area, so ground coffee loses aroma faster. If pre-ground coffee is the practical choice, keep the package tightly sealed and buy smaller amounts.
Freshness is not a cliff. Coffee does not suddenly become unusable on a particular day after roasting; it gradually loses aroma and becomes less expressive.