Work out hop substitution quantity instantly with clear inputs, formula shown and shareable results.
For bittering additions, substitute on alpha acid units: new mass = original mass x original alpha / substitute alpha. For late and dry hop additions, alpha acid is irrelevant and substitution should be by mass adjusted for the relative intensity of the oil profile.
Bittering substitution
Substitute mass = original mass x original alpha % / substitute alpha %
Aroma substitution
Substitute mass = original mass x relative aroma intensity
Aroma comes from essential oils, which do not track alpha acid. Substituting an aroma hop on alpha acid units gives the wrong quantity and the wrong character.
Alpha acid can be matched exactly, but cohumulone ratio and oil composition cannot. Published substitution charts group hops by character, and the result is always an approximation.