I ran to a LHBS yesterday to pick up some anti-foam additive. They carry a Five Star silicone based product instead of Fermcap S. Instructions were sparse. The guys at the LHBS had not used it before.
When there was just a hint of foam on the surface, I added two drops thinking it would form a protective barrier. This morning the krausen was about 2" thick. Added two more drops and the krausen fell a little in the center. A couple hours later, the krausen had rebounded and is about to enter the neck of the carboy.
Is this how these products are supposed to work? So far, I’m pretty underwhelmed.