Brew day
Mash and brewhouse efficiency
65% or 80%? Your efficiency is the number that makes all your recipes come out right.
Result
Fill in the values and run the calculation, or try the example.
This is the calculation Krausi uses. Create an account to save it in a recipe or a brew.
Create my accountWhy measure your efficiency?
No system extracts all the sugar from the malt. The share actually recovered is the efficiency. It depends on the crush, the sparge and the equipment, and it is specific to each brewer. Until you know it, every predicted gravity is a guess.
The tool separates two measurements. Mash efficiency, calculated before the boil, tells you whether the sugars were well extracted from the grain. Brewhouse efficiency, calculated on the fermenter, also counts what was lost in transfers and at the bottom of the kettle. Comparing the two shows where you lose.
How is efficiency calculated?
The potential is the sugar the wort would contain if everything were extracted. Efficiency compares this potential with what is measured:
potential = sum (kg × yield × 384)
efficiency (%) = gravity points × volume (L) / potential × 100Gravity points are (SG − 1) × 1000. The calculation is done twice: with the pre-boil gravity and volume, then with the original gravity and the volume in the fermenter.
Worked example
Values entered
- Fermentables:
- weight in kg 5, yield from 0 to 1 0.8
- Pre-boil gravity in SG: 1.04
- Pre-boil volume in litres: 25
- Original gravity in SG: 1.05
- Volume into the fermenter in litres: 20
Result from the tool
- Mash efficiency in %
- 65.1 %
- Brewhouse efficiency in %
- 65.1 %
- Potential of the fermentables in points·L
- 1536 L
What the tool does not do
- Volumes must be brought back to 20 °C and gravities corrected for temperature.
- Malt yields come from the maltster: an error in the yield ends up in the efficiency.
- A single measurement is not enough: average two or three brews.
Frequently asked questions
How can I improve my efficiency?
In this order: a finer crush, a slower sparge with water at 75 to 78 °C, then a mash pH between 5.2 and 5.6. A stable efficiency is worth more than a high one: it is what makes recipes predictable.
What is a normal efficiency with BIAB?
With a brew bag and no sparge, expect 60 to 70%. Squeezing the bag and crushing finer gain a few points.
And with the assistant?
On brew day, send your two gravities to Krausi: he calculates the efficiency and keeps it for your next recipes.
5 kg of Pilsner, 1.040 before the boil on 25 L, and 1.050 in the fermenter with 20 L.
Your efficiency is 65%, for both the mash and the brewhouse: you lose nothing in transfers. I've updated the efficiency of your setup; your next recipes will be calculated with it.