Brew Lab · Calculators I + II
Hop Bitterness Estimate
Estimate boiled-hop IBU with the Tinseth model while explicitly separating modeled IBU from perceived bitterness.
Boundary: This calculation is recipe analysis, not a recommendation to consume stronger or more bitter beer.
Static result contract
Worked example
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- Tinseth IBU estimate
- 28.8
- Additions modeled
- 1
- Boundary
- IBU ≠ perceived bitterness
Method
Formula is part of the interface
BEU does not hide the calculation behind a single result number.
| Method | Formula | Interpretation boundary |
|---|---|---|
| Tinseth utilization | U = 1.65 × 0.000125^(SG−1) × [1−e^(−0.04t)] / 4.15 | Model of hop alpha-acid utilization for boiled additions. |
| Tinseth IBU contribution | IBU = U × alpha_fraction × hop_g × 1000 / wort_L | Modeled concentration estimate, not a sensory bitterness score. |
Input contract
Units and guards
Input guards keep this foundation implementation bounded. They are not style definitions, legal thresholds, or equipment ratings.
| Input | Accepted units / range | Boundary |
|---|---|---|
| Post-boil volume | l, us gallon | Volume used for concentration estimate. |
| Wort gravity | specific gravity | Gravity used by Tinseth bigness factor. |
| Boiled hop additions | numeric | Weight, alpha-acid %, and boil time for each addition. |
Limits & safety
What the result does not prove
Limitations
- Actual lab IBU can differ from recipe estimates.
- Late/whirlpool/dry-hop bitterness chemistry is outside this foundation model.
- IBU does not equal perceived bitterness.
Safety / responsible-use notes
- This calculation is recipe analysis, not a recommendation to consume stronger or more bitter beer.
Methodology sources
Follow the method back to its references
External formulas and technical claims are sourced separately from Beer Universe's own algebra, unit handling, and interface policy.
- Tinseth IBU method reference
industry technical · recipe IBU estimation · Tinseth method context - BEU018 Brew Lab Calculators II methodology contract
beu original · BEU calculator guards · BEU interpretation boundaries · BEU result-route policy