PPG is points per pound per gallon, the maximum gravity contribution of a malt. It is the number of gravity points one pound of fully converted grain adds to one gallon of water. Base malts are about 37 PPG, while extract is higher because it is pre-converted and concentrated.

How is original gravity predicted from PPG?

Maximum points equal the grain weight times its PPG divided by the batch volume in gallons. Multiplying by your brewhouse efficiency gives the actual points you capture. Original gravity is then 1 plus those points divided by 1000, so 50 points gives an OG of 1.050.

What is brewhouse efficiency?

Brewhouse efficiency is the fraction of a grain's theoretical sugar that actually reaches your fermenter, accounting for mash conversion and losses to grain absorption, dead space, and trub. Most all-grain systems land between 65 and 80 percent. Extract brewers effectively run at 100 percent.

How do I handle a recipe with several grains?

Run each grain separately to get its gravity points, then add all the points together and convert the total to OG. Because gravity points are additive, this gives the same result as a full recipe calculator. Specialty grains contribute fewer points but still add to the total.

Why is my measured gravity lower than predicted?

A lower measured gravity usually means your real efficiency is below the figure you entered. Causes include a coarse crush, channelling in the mash, a short mash time, or higher losses than expected. Lower the efficiency input to match your actual results, then it becomes a reliable predictor for future batches.

Gravity Points Per Pound Calculator

The Gravity Points Per Pound Calculator predicts the original gravity a grain will contribute from its extract potential, weight, batch volume, and your brewhouse efficiency. It is the core arithmetic behind every recipe-formulation tool, and running it grain by grain lets you build or benchmark a recipe by hand.

How it works

Every malt has a maximum extract potential measured in points per pound per gallon, or PPG. A base malt at 37 PPG means one pound fully converted would raise one gallon of water by 37 gravity points. Spread the same grain over a larger batch and the contribution falls proportionally:

Max points    = weight (lb) * PPG / volume (gal)
Actual points = max points * efficiency
OG            = 1 + actual points / 1000

Efficiency is the fraction of that maximum you actually capture after mash conversion and losses. Most all-grain systems run 65 to 80 percent; malt extract is already converted, so it effectively runs at 100 percent.

Worked example

9 lb of 2-row pale malt at 37 PPG, into a 5.5 gal batch, at 75% efficiency:

Max points = 9 * 37 / 5.5 = 60.5
Actual points = 60.5 * 0.75 = 45.4
OG = 1 + 45.4 / 1000 = about 1.045

So that grain alone gives an OG near 1.045. Add the points from any other grains in the bill before converting the total to OG, because gravity points add up directly.

Tips and notes

To predict a full recipe, run each grain through the calculator, jot down its gravity points, and sum them. Specialty grains like crystal and roasted malts have lower PPG and contribute fewer points, but they still count. If your measured gravity comes in below the prediction, your true efficiency is lower than the value you entered. Common causes are a coarse crush, channelling in the mash, or higher equipment losses. Once you dial in the efficiency figure that matches your actual results, this calculator becomes a dependable predictor for every future batch on your system.