Dilution to Target Gravity

How it is calculated

The tool treats the sugar in the batch as a fixed amount that must be spread over a bigger volume. Gravity points are the part of the specific gravity after the decimal point, so 1.065 is 65 points. The amount of sugar is proportional to volume × points, which stays the same after dilution, so final volume = volume × current points ÷ target points and water to add = final volume − volume. Volumes are in US gallons and shown to two decimals. Enter points, not the full SG: the fields take 65, not 1.065. Volume and target points must be above zero, current points cannot be negative, and a target higher than the current gravity gives no result because water can only lower gravity. The method assumes water and wort volumes simply add, which is close enough for brewing use.

Common mistakes

• Typing the full gravity, such as 1.065, in a field that wants points. The tool gives about 0.07 gal, which looks plausible but is wrong.
• Entering a target higher than the current gravity. Water cannot raise gravity, so the tool shows no result; the wort would have to be concentrated, not diluted.
• Mixing litres and gallons. The volume field and the answer are in gallons, so a 19 litre batch is about 5 gallons.
• Forgetting that the diluted volume may not fit in the fermenter. Check the final volume as well as the water to add.
• Measuring gravity on hot wort, which reads low. Cool the sample to the hydrometer's calibration temperature before entering the points.