Calculate the bitterness (IBU) of your beer using the Tinseth formula. Add each hop addition to see how they contribute to the overall bitterness.
How IBU Is Calculated (Tinseth Formula)
We use the Tinseth formula, the most widely accepted method for estimating hop bitterness:
IBU = (mg/L of alpha acids) × Utilisation
Utilisation depends on boil time and wort gravity — longer boils and lower gravities extract more bitterness from the hops. A 60-minute boil typically gives around 25% utilisation, while a 15-minute addition might only give 12%.
IBU Ranges by Style
- 5–15 IBU — Wheat beers, light lagers, Berliner Weisse
- 15–25 IBU — Mild ales, Scottish ales, cream ales
- 25–45 IBU — Bitters, pale ales, porters, most stouts
- 45–70 IBU — IPAs, American pale ales, imperial stouts
- 70–100+ IBU — Double/Imperial IPAs, barleywines
Understanding BU:GU Ratio
The Bitterness Units to Gravity Units ratio tells you how balanced your beer is. Divide IBU by the gravity units (e.g., 1.050 = 50 GU). A ratio below 0.5 is malt-forward; 0.5–0.8 is balanced; above 0.8 is hop-forward. Most classic British bitters sit around 0.6–0.8.
Tips for Hitting Your IBU Target
- Bittering hops go in at 60 minutes — this is where most IBU comes from.
- Flavour hops at 15–30 minutes add moderate bitterness plus flavour.
- Aroma hops at 0–5 minutes (or dry hop) add almost no IBU.
- Higher alpha acid hops = more bitterness per gram. Use high-AA hops for bittering, low-AA for aroma.
- Higher gravity worts reduce utilisation — you need more hops in big beers.