Ask Mr. Wizard

The Importance Of A Diacetyl Rest


Donnie Maheu — Baton Rouge, Louisiana asks,

I am trying to determine the necessity and benefit of a diacetyl rest in lager fermentations. I have recipes from three different homebrew suppliers; one doesn’t suggest a rest, one recommends a few days, and another recommends one week. I am brewing small (2–2.5 gallons/7.6–9.5 L) at a time. Can you shed some light on this subject?

Diacetyl rests or colloquially known as d-rests, whether brewing lagers or ales, are good insurance policies to help ward off diacetyl. Many recipes focus on wort production and provide little in the
Response by Ashton Lewis.