Fermcap-S 1 oz.

SKU: 9152

An anti-foam agent that can be used during fermentation to eliminate messy blowoff. Can also be added during the boil to reduce the risk of boilovers.

Availability: In stock




An anti-foam agent that can be used during fermentation to eliminate messy blowoff. As soon as fermentation is over, this insoluble compound settles out and remains behind when the beer is racked. It will not affect the finished beers flavor, appearance or head retention. Can also be added during the boil to reduce the risk of boilovers. Use a few drops per gallon for boil, or two drops per gallon for fermentation. Comes in a one ounce eyedropper bottle. Keep refrigerated until use.

Additional Information

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Customer Reviews

A necessity. Review by Dan

I used it today for the first time, and it works as advertised. Boiled 3 gallons of wort in my 4 gallon stockpot, and there was no foaming at all. I only used 3 drops of Fermcap. I used 3 more drops in the fermenter, and there's no risk of a blowout now. (Posted on 12/21/14)
I never brew without this stuff! Review by Matt
I was very skeptical when I first bought my little bottle of Fermcap but holy cow does it work! No more boil-overs, no more blowoff; even when using a well-developed yeast starter, a few drops of this stuff and your blowoff worries are over. Helps when it comes time to clean your carboys too, there's a LOT less gunk to clean off your primary. (Posted on 10/27/14)
i would not brew with out this Review by jon doe
This stuff is awesome no fear of boilovers and no geysers blasting out of my carboys i have used this with all most all of my twenty plus brews and it is a steal for the time and trouble it saves . That being said there is only one thing that concerns me is i open the bottle twice for every brew and a bad batch gave me the fear of contamination and that was one of the few thoughts that crossed my mind luckily it was not that. just use caution in the handling of this and you should be fine (Posted on 8/28/14)
It saves marriages!!! Review by Andy
I travel for work almost constantly. So, after the third blow off my wife cleaned up because I was out of town, she kindly "suggested" I start using this stuff.

I use it on every beer I brew now and it works wonders...oh, and I'm still married, so I have that going for me, which is nice? (Posted on 8/11/14)
Just Works Review by Chris Graham
It seems like almost every component of the homebrew process has its pros and cons, but with this stuff there's no downside so I would recommend it to any homebrewer of any level without hesitation. During the boil it makes boil-over a non-concern, so you can get your ingredients in efficiently without having to worry about cleaning burnt wort off your burners afterwards. If you make a yeast starter (which you probably should be doing), you can make a big starter that barely fits in your flask and not have to worry about it making a mess on your counter. And once you've got everything in the fermenter, you can have your yeast be as fast and active as you want and not have to deal with a blowoff tube. All of that from just a few drops of this stuff, and by the time you serve the finished beer it will have settled out with the yeast and other particulates. Overall it helps you avoid some of the most annoying and common ways that brewing can get messy with no effort at all, so that you can focus on making tasty beer and having fun doing it. (Posted on 6/16/14)
Works Great Review by Matthew
Works great for reducing the possibility of a boil over!! (Posted on 12/16/13)
Awesome Product Review by Roger
I was getting sick of boil overs of wort and this product eliminated them. It also made it much easier to make my yeast starter on the stove. No more boil overs there as well! (Posted on 11/23/13)
Never brew without it Review by Dane
I first tried adding this stuff to the primary fermentor with a rising krausen an inch from the airlock. I left to find the blowoff tube, and came back two minutes later. The foam was already down to a dense 5/8" layer and it never rose again. Awesome stuff. I'll never brew without it again. (Posted on 9/28/13)
great for lessening blowoff in fermentation Review by PhilipCT
Added a few drops to fermenter post-chill. This was the first time I was able to run the aeration pump and stone for 30 minutes without stopping to let the fom subside, so this was a great result.

After, I had a really active fermentation, but I believe the Fermcap kept the krausen from going too crazy and travelling up the blowoff tube, as has happened to me the last few brews.

Checked my SG after 2 weeks of fermentation and we're down to 1.002 (not a typo!). So, I'd say the Wyeast Saison Yeast 3711 was unaffected by the Fermcap, which had been my only concern.
(Posted on 9/12/13)
Awesome Review by GetFunky
1st time user, it prevent boil over at hot break, and saved me a lot of clean up time. Well worth the price and effort. (Posted on 9/9/13)
It works! Review by Nick
I can't believe it took so long for me to use this, knocks heat break right down to help prevent boil overs. (Posted on 7/12/13)
Incredible stuff Review by Kevin
I use it in my starters, at the hot break and before primary fermentation. Zero boil-overs and no more need for a blow-off tube. I will always keep this on hand.

Thanks for the great recommendation from the MSP store staff! (Posted on 4/27/13)
Amazing..absolutely amazing! Review by Ian
I'm brewing a 5.5 gallon ESB as I type this. It's behind me, with my back to the kettle and I'm three minutes into the boil. I have an 8 gallon kettle, and collected 7.25 gallons of runnings. Yep, that means I"m at a full boil with 7.25 gallons, .75 gallons to spare and I'm not even watching it.

Absolutely amazing! Neither I, nor Northern Brewer endorse the stupidity I'm displaying at this moment - but wow this is amazing stuff! (Posted on 2/11/13)
Works as advertised Review by OPJohn
Fantastic product. I use 1 drop per gallon during the hot break and an additional drop per gallon just after pitching the yeast. Even on monster high gravity beers with aggressive yeast strains, it's kept the krausen of my beers at or below 1" in my primary fermenters. Kiss your blow off tubes goodbye. (Posted on 12/23/12)
Must have for brew day Review by Jefferson
I have never tried this product in fermenter but was boil a stout batch today. Seen a boil over developing and grabbed this stuff out of the fridge. A few drops and was under control. (Posted on 12/8/12)
The Best Kept Secret in Brewing! Review by Adam
The other reviewers are absolutely correct. This product is nothing short of amazing. It works well on the hot side, preventing kettle boilovers. It works in the fermenter, preventing plugged up airlocks and beer covered ceilings. The really amazing part is that it does all that, but doesn't affect head retention once the beer is clarified. I recommend ordering at least two bottles; once you try this product, you will not want to run out. (Posted on 10/24/12)
Goodbye boil overs! Review by Dwight
Nice to worry less about boil overs. It's also extremely useful in erlenmeyers when boil starter so it doesn't boil over. I still get violent fermentation and need blow off, but that's an easy remedy. (Posted on 10/23/12)
This stuff is magic Review by Natrix
Significantly decreases the probability of a boil-over when added to the boil and cuts down on the amount of foam generated during primary fermentation. It says 2 drops per gallon, but I find that 1 drop per gallon is usually enough. I usually add about 3 drops at the start of the boil and another 3 drops to the primary. I also use 1 drop in starters. (Posted on 7/28/12)
Great for starters Review by Joshua
No more worries about the hot break assaulting me as I prepare yeast starters in an erlenmeyer flask. Does what it says. (Posted on 7/5/12)
Must Have Brewers Aid Review by Fred
I used this for about twenty brews and took it for granted. I ran out of this and was chained to the kettle during the first half hour. Constantly turning off the burner to stop boil overs. Constant problem with over flowing carboys too. MUST HAVE! (Posted on 5/9/12)
Great in starters Review by Dave
Billions of lives have been saved by using this product. Vigorous starters would push out the foam stopper and spill healthy yeast all over my stir plate. One drop and the problem is gone. (Posted on 2/20/12)
amazing Review by shaun
used for the first time last night. used 1 drop per gallon in the boil and did not even have a bit of hop residue on the side of the pot and no foam on the surface. this morning added an additional 1 drop per gallon to the fermenter that is bubbling away although the beer surface is smooth!

if only I knew about this when I was dealing with blowoff from my 11% bourbon coffee imperial stout! (Posted on 1/30/12)
Saves a lot of clean up. Review by Brendan
I've been using Fermcap-S for the last couple of years or so. I add it to the boil (2 drops/gallon). This addition takes care of foam both during the boil and fermentation. I haven't had a boil-over or major blow-off since.

I also use it for my yeast starters. I use a 2000ml Erlenmeyer flask with DME/water boiled on the stove. 1 drop of Fermcap-s prevents any sudden boil-overs.

Well worth it for the piece of mind and to never hear that terrible scorching hiss of a boil over again.

In my experience, it has no effect on head retention. (Posted on 1/18/12)
I agree with Lonnie Mac Review by bille
Boil starters on your stove or ever plan on it? Ferment 5.5g in a 6g Better Bottle? Volume in your kettle on the high side and/or do you wish the hot-break would hurry up and get out of the way so you can get on with your boil and start adding hops?

If you answered yes to any of these then you definitely need foam stabilizer. Word to the wise, even though you don't use much of it, don't run yourself out of this stuff. I did and now I'm paying. None of the LBHS around here carry it and NB is out of stock. Things will certainly get messy. (Posted on 12/18/11)
Really does what it says Review by Aaron
I had my doubts, but I boiled 6.75g in a 7.5g pot without an issue. Amazing. I haven't tasted the beer yet, but I'm looking forward to it. (Posted on 12/12/11)
excellent Review by David
Personally I wouldn't brew without it. If you haven't used the product, it is simply food grade silicone. It's effect is to drastically reduce the surface tension of the foam. I place a few drops on the carboy stopper when I am fermenting. If the kraeusen makes it way to the top of the carboy the Fermcap knocks it down very fast. It is also a very valuable addition in the brew pot. (Posted on 9/11/11)
amazing Review by the beer baron
I can't believe i didn't start using this until now. No more boilovers, gushing carboys, and better hop utilization? I'm never brewing without this again (Posted on 3/28/11)
GREAT product Review by Jeff
I wouldn't think of not using this in every batch I ferment. NEVER have a blow out and it even makes for better head retention. I panic when I start running low of this stuff. (Posted on 8/30/10)
awesome Review by yellowthere
pretty much the greatest thing to happen to brewing in years. I use to prevent boil overs and in the fermentation. It works perfectly, I've never had a problem. (Posted on 8/4/10)