The short answer
- Coffee's enemies are oxygen, light, moisture and warmth. A vacuum-sealed, light-proof bag in a cool cupboard deals with all four.
- Buy beans, not ground: ground coffee goes stale much faster. Grind just before brewing.
- Freshly roasted beans give off gas for the first days. Let them rest before sealing them tight, or the bag puffs up.
- For months: seal week-sized portions and freeze them, and let a bag come to room temperature before you open it.
Why coffee goes stale
The aroma of roasted coffee sits in delicate oils and volatile compounds. Oxygen breaks them down, light and warmth speed that up, and moisture makes beans dull and can let mould in. Ground coffee has many times the surface of whole beans, so it loses its aroma much faster.
A vacuum sealer takes the oxygen out and keeps moisture out. A light-proof bag or a dark cupboard deals with light, and a cool place, or the freezer, with warmth.
Fig. 12 · What protects coffee
Five ways to keep beans
What each one keeps out. Warmth depends on where you keep it: always cool, away from the stove and sun.
| Storage | Oxygen | Light | Moisture | Warmth |
|---|---|---|---|---|
| Shop's bag, opened and clipped | Partly | Yes | Partly | Cupboard |
| Clear jar on the bench | No | No | Yes | Bench |
| Vacuum container in the cupboard | Yes | Yes | Yes | Cupboard |
| Vacuum-sealed metallised bag | Yes | Yes | Yes | Cupboard |
| Sealed metallised bag, frozen | Yes | Yes | Yes | Yes |
The catch with fresh roast
Roasting leaves carbon dioxide in the beans, and they give it off over the first days. That's why roasters pack coffee in bags with a one-way valve. Seal very fresh beans tight and the gas puffs the bag up again.
Let freshly roasted beans rest a few days in their valve bag before you seal them. Beans that were roasted a while ago have given off most of their gas and can be sealed straight away.
Store it by when you'll drink it
This week
Keep the beans in a vacuum container in a cupboard, and pump the air out again after each time you open it.
Helps: G-Line glass containers
This month
Split the beans into portions and seal each in a light-proof metallised bag. Open one at a time; the rest stay sealed, dark and cool.
Helps: Metallised vacuum bags
The months after
Seal week-sized portions and freeze them. Take out one bag at a time and let it come to room temperature before you open it: cold beans in warm air collect condensation. Don't put thawed beans back in the freezer.
Ground coffee
If you buy it ground, seal it in small portions, because every opening lets air at it. Fine powder can be drawn towards the seal: lay a folded strip of paper towel inside the bag just below the seal line, or use a vacuum container.
Not the fridge
The fridge is damp and full of smells, and coffee takes on both. Each time a cold bag is opened, condensation settles on the beans. A cool, dark cupboard is better for coffee you'll drink soon, and the freezer, sealed, for coffee you won't.
LAVA AustraliaOfficial LAVA distributor and vacuum-packaging specialists since 2018.
