# Top-down Brew: Grain Weights to Percentages

## Purpose: To determine the percentages of a grain bill by weight and by specific gravity.

Mash efficiency percentage

Enter weight and select malt type. The empty field on the right is for entering custom yield in either specific gravity or coarse-grind as-is percentage.

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## Results

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## Discussion

This calculator converts a recipe grain bill weights into percentages by gravity points. The percentages are based upon each malt or sugar's gravity point contribution to the wort divided by total gravity points. These percentages can be used to build grain bills based on percentages for the Beer Engine 2024 calculations.

Percentages by gravity and percentages by weight are not always equal because various malts or sugars contribute less or more to gravity points to the wort for an equal weight. For example, 1 pound of sugar contributes more gravity (1.046) than 1 pound of malt (1.037). A hypothetical grain bill of 10% sugar (sucrose) by weight and 90% two-row malt will make a wort that is 15.4% sugar.

The calculations adjust the mashed grains downward based upon mash efficiency. Most recipes assume a mash efficiency. For example, the recipes published in BYO magazine assume a 65% mash efficiency. This adjustment is not necessary for sugars.

The calculations focus upon gravity points because this is the expression of yield that homebrewers are most familiar with.

The weight units - metric or US - do not matter for calculating percentages.

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This work is licensed under a Creative Commons Attribution 4.0 International License.