Brewhouse Efficiency Calculator
Brewhouse efficiency is the percentage of a grain bill's potential extract that ends up as dissolved sugar in the fermenter. It is calculated as (measured gravity points × batch volume) / (grain weight × malt yield), accounting for losses in the mash, lauter, boil and transfer. A typical home system lands between 65% and 78%.
Efficiency is the single number that makes a recipe predict your gravity correctly. Measure it once, put it in your equipment profile, and stop guessing.
What efficiency measures
Malt contains a fixed amount of extractable sugar. Brewhouse efficiency is the fraction of it that ends up as gravity points in your fermenter — after the mash, after the sparge, and after everything you left behind in the tun, the kettle and the trub.
efficiency = points extracted / points available
where points extracted is (OG − 1) × 1000 × batch volume in gallons, and points available is grain weight in pounds × the malt’s PPG rating.
PPG — points per pound per gallon — is roughly 36–37 for pale base malts, lower for crystal and roast, and near zero for adjuncts like rice hulls. If you do not know yours, 36 is a reasonable starting figure for a grain bill that is mostly base malt.
What is normal
- 60–65% — brew-in-a-bag without a squeeze, or a first all-grain batch
- 70–75% — a typical batch-sparge or fly-sparge home system
- 75–80% — a well-tuned system with a good crush and an efficient sparge
- 80%+ — usually a fine crush, a long sparge, or a measurement error somewhere
The number matters far less than its consistency. A brewery that reliably hits 68% produces better beer than one that swings between 62% and 78%, because only the first can plan a recipe.
Mash efficiency vs brewhouse efficiency
Mash efficiency measures conversion and extraction into the kettle. Brewhouse efficiency measures what actually reaches the fermenter, so it also carries kettle and trub losses. Brewhouse efficiency is the lower figure, and it is the one recipe software should use — it is what determines the gravity of the beer you will drink.
Raising it
- Crush finer. The single biggest lever. Mill gap is where most low efficiency comes from.
- Sparge more slowly, or batch sparge in two even runnings rather than one.
- Mash longer. Sixty minutes is a convention, not a law; ninety often gains a couple of points.
- Reduce losses. Wort left under the false bottom or in the kettle is gravity you paid for and did not get.
Brewhouse Efficiency Calculator — questions
What efficiency should I put in my recipe software?
Whatever you actually measured, averaged over your last few batches. A default of 72% or 75% is a guess about someone else's brewery, and it is the most common reason calculated gravity does not match measured gravity.
Why did my efficiency drop on a big beer?
Efficiency falls as grain bill grows, because a thicker mash and a shorter effective sparge extract proportionally less. A system that hits 75% on a 1.050 beer may see 65% on a 1.090 one. That is normal — plan for it rather than fighting it.
Does efficiency affect flavor?
Not directly. Chasing very high efficiency by over-sparging can extract tannins and produce astringency, which is why most brewers stop pushing once they are consistent.
Your efficiency, baked into every recipe
Set your efficiency once in Brewgravity's equipment profile and every recipe predicts gravity to match your system — no more guessing or re-entering numbers.
There will always be a free plan · no credit card · drag in BeerXML or BeerJSON