Hops Storage

BrewCo Brew Tools

Hops lose bittering power in storage. Use this calculator to estimate how much alpha acid your hops have left based on how long they've been stored, and how well.

How to use it

  1. Enter the alpha acid % printed on the packet at harvest.
  2. Enter how many months they've been in storage.
  3. Choose the storage condition that best matches yours.
  4. Read off the estimated remaining alpha acid %.
— % AA
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How should I store hops?

Keep them sealed, cold, and away from light — ideally frozen. Alpha acids degrade steadily at room temperature, and much more slowly (but not zero) when frozen. Once opened, fold the pack tightly to push out air and use within a few months for best results.

More free home brew calculators

Browse our full range of hop pellets at BrewCo UK — nitrogen-flushed, T90 pellets from £5.99.

How hop storage affects bitterness

What it does: hops slowly lose their alpha acids, the compounds that give bitterness, as they age. This calculator estimates how much bittering power your hops have left, based on how long and how well they have been stored.

How to use it: enter the alpha acid percentage printed on the pack, the number of months since harvest or packing, and choose the storage condition that matches yours.

The formula in plain words: each storage condition has an assumed loss per year: about 2% frozen and vacuum-sealed, 5% in a sealed bag in the fridge, 15% in a cool cupboard and 35% at room temperature unsealed. The calculator applies that loss over the number of months you enter.

Worked example: hops packed at 6.0% alpha acid, stored for 6 months in a sealed bag in the fridge, come out at about 5.8%, roughly 97% of their original bitterness. The same hops left unsealed at room temperature drop to about 4.8%.

Take the adjusted figure to the hops alpha adjustment calculator to work out how much to use. The results are an estimate, and aroma fades faster than bitterness, so fresh hops are still best for late and dry-hop additions.

Frequently Asked Questions
What is the best way to store hops?
Keep them sealed, cold and dark. The freezer is best. Once a pack is opened, squeeze out the air, seal it tightly and use it within a few months.
Do old hops go off?
They don't usually become unsafe, but they lose bitterness and aroma, and very old hops can smell cheesy. Use your nose: if they smell stale, buy fresh ones.
Does this work for aroma as well as bitterness?
No. The calculator estimates alpha acid, which gives bitterness. Aroma oils fade faster, so late and dry-hop additions need the freshest hops you can get.