It does work in the fermenter, but you may have to reapply it from time to time, which puts you above the recommended dosage. I have had a couple of blowoffs even after using it, but it usually does a decent job. I suspect Fermcap-S would be a better choice.
The Fiesty(sic) Goat Brewery est. 2007 & Clusterfuggle Experimental Ales est. 2009
Planned: Dark Mild w/ 002, Dark Mild w/ 028, sLambic II, Flanders Red II
Primary: Fat Man Porter w/ 1469, Fat Man Porter w/ 005, sLambic I
Secondary: Orange Blossom Mead, Flanders Red I
Kegged: Centennial Falcon w/ Conan, Centennial Falcon w/ Denny's, Barrel-aged Fat Man Porter, Belgian Dark Strong, Huell Melon Pale Ale
Bottled: Flanders Red I