Brewhouse Efficiency Calculator

Calculate your mash or brewhouse efficiency from your grain bill and the volume and gravity you collected, in metric, US or imperial units.

Brewhouse efficiency is the gravity points you collected, times the volume, divided by the most your grain bill could give. 4.5 kg of base malt and 0.5 kg of crystal malt can give about 1,494 points × liters; collecting 23 L at 1.044 gives 1,012, an efficiency of about 68%.

Reviewed by Diego Santiago, Professional Brewer

Volume into the fermenter (L)

Cooled wort in the fermenter

Original gravity (SG)

Measured at the calibration temperature of your hydrometer

Grain 1

Grain (kg)

Maximum potential (L°/kg)

From the malt sheet (hot water extract); about 300 L°/kg for base malt

Grain 2

Grain (kg)

Maximum potential (L°/kg)

From the malt sheet (hot water extract); about 300 L°/kg for base malt

Brewhouse efficiency67.7%Gravity points collected / possible1,012 / 1,494points × L

Results are estimates provided "as is," for informational and planning purposes only, without warranties of any kind. Check them before you rely on them: you are responsible for decisions about your beer and equipment, including pressure and carbonation levels, the pressure ratings of your kegs and fittings, and any alcohol content you declare. Use of this calculator is subject to our Terms and Conditions.

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How efficiency is calculated

Each grain has a maximum extract potential: the gravity points it would give if every bit of its extract reached the wort. Efficiency compares what you collected with that maximum:

E = \frac{G \times V}{\sum m_i \times P_i} \times 100\%

where $G$ is the measured gravity in points (1.044 is 44 points), $V$ the volume, and $m_i$ and $P_i$ the weight and potential of each grain. With $V$ in liters and $m$ in kilograms, $P$ is in points per kilogram per liter (L°/kg); with US gallons and pounds, in PPG.

Use the pre-boil volume and gravity for mash efficiency, and the volume and original gravity in the fermenter for brewhouse efficiency.

For example, 4.5 kg of base malt (36 PPG, about 300 L°/kg) and 0.5 kg of crystal malt (34 PPG) can give at most about 1,494 points × liters. Collecting 23 L at 1.044 in the fermenter is 1,012 points × liters, a brewhouse efficiency of about 68%.

Inside Foambyte, each brewhouse profile keeps your efficiency, and the recipe studio uses it to estimate the original gravity of every recipe.

Reference table

Original gravity by brewhouse efficiency (rows) for base malt at 36 PPG (300 L°/kg) and common batch sizes (columns)
Efficiency	5 kg in 23 L	4.5 kg in 20 L	10 lb in 5 US gal	12 lb in 6 US gal
55%	1.036	1.037	1.040	1.040
60%	1.039	1.041	1.043	1.043
65%	1.042	1.044	1.047	1.047
70%	1.046	1.047	1.050	1.050
75%	1.049	1.051	1.054	1.054
80%	1.052	1.054	1.058	1.058
85%	1.056	1.057	1.061	1.061

Sources

John J. Palmer. How to Brew, Brewers Publications, 2006. Efficiency as collected gravity points divided by the grain bill's maximum, typical base malt potential (36 PPG as-is) and the PPG to L°/kg conversion (chapter 18); 3rd edition, online version with the author's updates.

Frequently asked questions

What is the difference between mash and brewhouse efficiency?

Mash efficiency measures how much of the grain's extract reaches the kettle, from the pre-boil volume and gravity. Brewhouse efficiency measures how much reaches the fermenter, so it also counts wort lost to trub, hops and the chiller. Recipes are usually planned with brewhouse efficiency.

What is a good efficiency?

Many homebrewers get between 65% and 80% brewhouse efficiency. Consistency matters more than a high number: a steady efficiency lets you predict your original gravity, and you can scale the grain bill to it.

Where do I find the grain potential?

On the malt's analysis sheet, as extract (fine grind, as-is or dry basis) or hot water extract. Multiply the as-is extract percentage by 46 to get PPG, or use hot water extract directly in L°/kg. About 36 PPG is typical for base malt.

Why is my efficiency low?

Common causes are a coarse crush, a mash that did not fully convert, a mash pH far from about 5.2 to 5.6, or sparging too fast. Measuring the volume or the gravity at the wrong temperature also skews the result.

Why did I get more than 100%?

The potential is a laboratory maximum, so a result above 100% points to a measurement error: the volume, a gravity reading taken hot without correction, or a grain potential set too low.