[Jimmy K]

Where did you hear that?

Answer my own questions with Google.
 

"Brewers should not use silicone-containing antifoam for unfiltered beers. The FDA allows active silicone to be used up to 10 parts-per-million (ppm) but stipulates that the silicone must be removed prior to packaging by either filtration or centrifugation. In the case of unfiltered beers, use a food grade, non-silicone antifoam. We sell a food grade, canola oil based antifoam that works well for this purpose and has an added benefit of being yeast-friendly at the same time. Look for my article on antifoams in the brewery in the July/August issue of The New Brewer. Please contact me directly if you would like to discuss this or any other matter further.
Cheers!
Dana Johnson Brewery Technical Representative BIRKO Corporation Henderson, Colorado www.birkocorp.com:

[denny]

Since I found out that Fermcap is supposed to be filtered out, I've cut way back on my use of it.  For instance, I've gone back to using a spray bottle of water to control the boil.  I"ll still use it when I have to, but I use as little as possible and avoid it if I can.

Where did you hear that?

Probrewer forum and data from one of the wholesalers who sells Fermcap.

" It is adsorbed onto the surface of the yeast, vessel walls and filter media. "

http://www.brewerssupplygroup.com/FoamControl.html

[Jimmy K]

I thought the site I found said that only Fermcap S must be filtered, Fermcap AT does not. No real distinction on your link.
 
I only use it in starters, but that makes me wonder. Good old paying attention works for the kettle.

[denny]

I thought the site I found said that only Fermcap S must be filtered, Fermcap AT does not. No real distinction on your link.
 
I only use it in starters, but that makes me wonder. Good old paying attention works for the kettle.

I had heard that also, so I bought some AT.  But I've come around to your way of thinking...I use a little for starters, but I'm back to using a spray bottle for the kettle.

[PSUhomebrewer]

Fermcap also seems to be degraded when exposed to longer boils (90-120 min). I recently did a batch where I over sparge by alot (though the ph and gravity wee all still above the warning area [1.018 and ph was around 5.5]). I ended up with about 9-11g of liquid for a 5.5g batch. I ended up boiling for roughly 4 hrs and had to add 2 additions of fermcap, since the first stopped after 90-120 minute mark.

[Pinski]

The only thing I've used it for recently has been to keep my blow-off receptacle from foaming all over the place while I'm at work and crapping up my fermentation freezer.