Diacetyl Formation Facts Written by Dr. Chris White
Some yeast strains produce a lot of diacetyl, while others produce less. Choose yeast that produces less, unless you are brewing a style that allows for the presence of diacetyl.
High fermentation temperatures promote diacetyl production.
Low aeration levels when yeast is pitched will produce less healthy yeast, which are prone to higher diacetyl production.
Ale fermentations produce more diacetyl because ales are fermented warmer than lagers, but the reduction happens much quicker.
Lager fermentations need to be given a “diacetyl rest” by increasing the fermentation temperature just before completing fermentation.
A hydrometer should be used to measure the specific gravity to calculate when to start the diacetyl rest. Begin when the beer reaches two to five points of final gravity.
The fermentation should never be rushed. Give the beer ample time for maturation.
Sanitize well, particularly when bottling, to limit the effect of diacetyl from bacterial contamination.https://byo.com/article/brewing-science-controlling-diacetyl/
Sent from my iPad using Tapatalk