Grain Bill Calculator

How it is calculated

The tool works out how many gravity points your batch needs and divides by what a pound of grain delivers on your system: points = (OG − 1) × 1000 × volume and grain (lb) = points ÷ (PPG × efficiency ÷ 100). OG is the target original gravity as a specific gravity (1.050, not 50), volume is the batch size in US gallons, PPG is the malt's potential in points per pound per gallon, and efficiency is your brewhouse efficiency in percent. The answer is in pounds with two decimals; there is no metric mode. The whole bill is treated as one malt with a single PPG, so for a mixed bill use a weighted average PPG. OG must be above 1, volume and PPG above zero, and efficiency above 0 and at most 100, otherwise there is no result.

Common mistakes

• Typing the gravity as 50 or 1050 instead of 1.050. The tool expects a specific gravity between 1.000 and 1.200, so 50 shows no result.
• Entering the batch size in litres. The field is US gallons, so 19 litres entered as 19 gives 34.23 lb instead of about 9 lb; convert to about 5 gallons first.
• Using the malt's lab-rated extract or mash efficiency instead of your brewhouse efficiency, which is the figure that actually reaches the kettle.
• Entering efficiency as a fraction (0.75). It is a percentage, so 0.75 gives about 900.90 lb of grain. Values above 100 are rejected.
• Typing PPG as a gravity (1.037) rather than points (37). The tool accepts it and returns 321.44 lb.