Hop Substitution & AAU Calculator
Swap one hop for another by alpha acid, and compute alpha acid units (AAU).
Amount the recipe calls for
α% of the hop in the recipe
α% of the hop you have
11.7 g
AAU of the original4.9
How it works
To swap hops while keeping the same bitterness, scale the weight inversely with alpha acid. A 12% hop substituting for a 5% hop needs less than half the weight. The ratio is unit-agnostic, so the answer comes back in whichever unit you entered.
new weight = original weight × original α% / new α%
AAU = oz × α%
Sources: alpha-acid substitution and AAU method from Brewer's Friend.
Matches bittering only - aroma and flavour differ between varieties.
Frequently asked questions
- How do I substitute one hop for another?
- Match the bittering contribution by scaling on alpha acid: new weight = original weight × original α% / new α%. A higher-alpha substitute needs less weight to deliver the same bitterness.
- What is an AAU (Alpha Acid Unit)?
- An AAU is the weight of hops in ounces multiplied by their alpha acid percentage. It is a quick measure of bittering potential - 1 oz of 5% hops is 5 AAU.
- Does this preserve hop aroma and flavour?
- No. This matches bitterness only. Aroma, flavour and oil profiles differ between varieties, so choose a substitute with a similar character and adjust late additions to taste.