Food grade foam inhibitor widely used in commercial brewing.
Two uses in one:
During Wort Boil: Helps prevent boil-overs allowing more aggressive boiling. Will not affect the head on the finished beer as it settles out and will not move to the beer after racking.
Usage: 3 drops per gallon of wort boil
During Fermentation: Keeps krausen in fermenter to 1/2". Allows for greater volume of high-gravity beers, and helps prevent clogged airlocks
Usage: 2 drops per gallon of fermentable product