Brewhouse efficiency calculator
Efficiency is the fraction of the sugar theoretically in the grain that ends up in the fermenter. It is the single most useful process number a brewer has.
points per kg per litre
Pale malt is about 308 points per kg per litre, equivalent to 1.037 per pound per gallon.
Brewhouse efficiency
67.53%
- Grain for the target gravity
- 5.769
- Gravity points achieved
- 52.0
- Points at 100% efficiency
- 77.0
- Potential in points per pound per gallon
- 36.9
- Effective extract
- 3.377
- Gravity that grain bill would give
- 1.0600
Show the working
- Grain bill = 5
- Grain potential = 308
- Volume into the fermenter = 20
- Measured original gravity = 1.052
- Target gravity for the reverse = 1.06
- Gravity points achieved = (1.052 - 1) * 1000 = 52
- Points at 100% efficiency = 20 > 0 ? 5 * 308 / 20 : 0 = 77
- Brewhouse efficiency = 77 > 0 ? 52 / 77 * 100 : 0 = 67.5325
- target_points = (1.06 - 1) * 1000 = 60
- Grain for the target gravity = 67.5325 > 0 && 308 > 0 ? 60 * 20 / (308 * 67.5325/100) : 0 = 5.769 23
- Potential in points per pound per gallon = 308 / 8.3454 = 36.9066
- Effective extract = 5 * 67.5325/100 = 3.376 62
- Gravity that grain bill would give = 20 > 0 ? 1 + 5.769 23 * 308 * 67.5325/100 / 20 / 1000 : 0 = 1.06
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- efficiency = actual gravity points / (grain x potential / volume)
- grain needed = target points x volume / (potential x efficiency)
A finer crush raises efficiency until the husks tear and the mash sticks. That trade-off is what sets the practical ceiling.
Efficiency falls with very high gravity worts, because the sparge cannot rinse as much sugar out.