IBU Calculator (Tinseth)
Estimate the bitterness a single hop addition adds to your beer with the Tinseth formula. Enter the hop, boil time, batch volume and wort gravity.
How to calculate IBU
- Enter the hop alpha acid percentage and weight in grams.
- Set the boil time, post-boil volume and wort gravity.
- Read the IBU and hop utilization the Tinseth model predicts.
Examples
60 minute bittering charge
5% AA, 28 g, 60 min, 20 L, OG 1.050
IBU 16.1, utilization 23.1%
Frequently asked questions
What is the Tinseth formula?
Glenn Tinseth's model multiplies a gravity bigness factor by a boil-time factor to get hop utilization, then scales it by the alpha acid concentration to give IBU.
Why does higher gravity lower utilization?
Denser wort isomerizes fewer alpha acids, so the bigness factor 1.65 x 0.000125 ^ (OG - 1) shrinks as gravity rises, reducing IBU.
Does this cover multiple hop additions?
It estimates one addition at a time. Add the IBU from each addition together to get the total bitterness for the recipe.
Should I use pre-boil or post-boil volume?
Use the post-boil batch volume in litres. That is the volume the finished bitterness is dissolved into.
Why are whirlpool and dry hops different?
Tinseth models a rolling boil. Whirlpool, hop stand and dry hop additions follow other curves, so treat their IBU contribution separately.
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