Beer Recipe Scaling Calculator
Found a recipe built for a different batch size, or moving to a new system? Enter the original and new volumes and your recipe amounts to scale grain, hops, yeast, and water — with an optional efficiency adjustment for the grain bill.
Leave these equal to scale grain by volume only. A lower new efficiency raises the grain bill.
Formula & how it works
The volume ratio is new ÷ old. Hops, yeast, and water scale by that ratio directly. Grain also scales for efficiency: grain × ratio × (old efficiency ÷ new efficiency).
Yeast is shown both as the exact scaled figure and rounded up to whole packs, since you cannot buy a fraction of one.
Worked example
Doubling a 5 gallon recipe to 10 gallons at the same efficiency gives a ×2 scale: 10 lb grain becomes 20 lb, 3 oz hops become 6 oz, 7 gallons of water become 14, and 1 yeast pack becomes 2. If the new system runs at 65% instead of 72% efficiency, the grain rises further to about 22.2 lb to hit the same gravity.
Scaling a recipe well
Most things scale linearly
Grain, hops, water, and yeast all scale in proportion to batch volume as a first pass, which is why a good recipe translates cleanly between sizes. Keeping the same amount per gallon preserves the gravity, bitterness, and color you liked in the original.
Efficiency is the exception for grain
The one thing that does not travel between systems is mash efficiency. A bigger mash tun, different crush, or new sparge routine can extract more or less sugar per pound of grain. When your efficiency changes, the grain bill has to change with it to reach the same original gravity, which the optional efficiency fields handle.
Verify the sensitive numbers
Once scaled, two things are worth a second look on a new system: bitterness, because hop utilization depends on boil volume and gravity, and water, because boil-off rates differ between kettles. Running the scaled hops through an IBU calculator and checking your pre-boil volume closes those gaps.