Low/No Pressure Fermenting

[daveyohill]

After re-listening to the Jamil fermentation Sunday Session episodes and after reading his "Mild" style entry in this months BYO mag I'm ready to "chance" a "no pressure" fermentation on my Hopped Up British Pale Ale. If you recall in one of those episodes Chris White gives Jamil props for recommending just wrapping the top of the primary fermenter carboy with foil.

I plan to ferment with re-hydrated Safale S-04 at 68ºF and will add no water to the airlock on my plastic bucket primary fermenter. I will drape a piece of tin foil over the airlock and onto the lid of the fermenter to provide some rudimentary dust protection.

I've been itching to try open fermentation for awhile and this method seems to offer the benefits without the obvious concerns of a wide open bucket.

Has anybody tried a similar fermenting routine? What was the outcome?

Does anybody have concerns about this strategy?

I've had great success with the Safale S-04 and use it as my main ale yeast. I guess I feel like I can predict what my fermentation will be like with this yeast but have always used a partially filled airlock. How will the yeasts performance change?

I don't do any secondary with my ales and typically leave them in the primary for two weeks. My last "Prim'nProper Pale Ale" is what they'll be serving in heaven!

Cheers, Davey O'

[yellowthere]

I'm not sure if Aluminum foil over the top of a carboy, or in your case over the airlock, is a full open fermentation. It's a partial or something, right? Same difference though. Any who I've done it in a secondary, by putting sanitized Aluminum foil over the top of the neck of the carboy. I put the foil as tight as I can, but don't use any kind of rubber band or anything to close it really tight. I've never had any problem. I do this if I don't have an airlock and bung clean and ready. On a carboy (I know that you are using a bucket, but still) I would be concerned about really active primary fermentation lifting the foil off entirely, then the krausen lowering back down over time, exposing the beer to everything. Shouldn't be a problem with a bucket though.

yellow.

[chefchris]

Drinking on an IPA now that was in a carboy. Let ferment out a week before adding dry hops and waiting another two weeks. No secondary and only tin foil over the opening of the carboy. Like I said, I'm drinking it now ... so it works.

[Kaiser]

Do you guys really see a difference between water in the airlock and no water? The pressure difference is very small and comparable to an elevation difference of only 50ft.

Kai

[wunderbier]

My understanding is that the partial pressures of CO2 and O2 will begin to equalize with atmospheric conditions after CO2 production ends if you don't fill the airlock by that point. So, be careful of that. There won't be any concern of additional bacterial contamination as demonstrated by Pasteur's swan neck flask experiment, but oxidation will take place. But, if Kai's calculations are correct, it doesn't sound like there's any point to it unless you go all the way and ferment sans lid.

*edit* Yeah, listening to Dr. White on the Saison episode of The Jamil Show, use a filled airlock after high kräusen.

[bashcraft]

Do you guys really see a difference between water in the airlock and no water? The pressure difference is very small and comparable to an elevation difference of only 50ft.

Kai

I'm betting there is no difference. Without some very expensive equipment, I don't believe you could even measure the pressure difference.