foil ok on secondary?

I am splitting a batch into containers of different kinds of fruit. I haven't got enough airlocks for these, even if the airlocks fitted.

Can i simply cover the lids well with sanitized kitchen foil like i would a starter?

Theoretically, yes. I'd be somewhat concerned, though, that the suspended yeast in your beer will start fermenting the sugars in the fruit. This, of course, will release CO2. If you simply cover your secondary with foil, pressure will build up, and bust through the foil. Be sure both the beer and the fruit are cold, and you should be fine.

Yeah it's fine. I use foil on all my carboys during primary fermentation. If you're racking onto fruit, fermentation should start up again and the beer will be protected by the co2. Pressure doesn't really build up under the foil since the foil doesn't create a tight seal.

jrkettle said:

Yeah it's fine. I use foil on all my carboys during primary fermentation. If you're racking onto fruit, fermentation should start up again and the beer will be protected by the co2. Pressure doesn't really build up under the foil since the foil doesn't create a tight seal.

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+1 its true. I use foil half the time and pressure is no issue

If you are concerned about it you could do this.

Get your square of foil, poke a pencil sized hole in the center. Take another small 1x1 or 1/2x1/2 inch square piece of foil (cling wrap would be better) and tape it down over the hole, but only on three sides.

Star san and place the foil over the carboy mouth and rubberband down.


Any build up of CO2 will escape through the hole, once the over presure is gone it will give an ok seal from anything airborne. I'd give it a shot of star-san every day or so to be safe.

Edit: The issue you run into when using a "secondary" is that there usually is not as much CO2 do displace the air and keep out the nasties like during primary fermentation.

On a side note this method works for sucking chest wounds also.

cool thanks, it wasn't the pressure i was worried about it was more infection concerns and hopefully the fruit starting up fermentation again will purge the air from the fermenters so no worries.

Infection from the particles in the air is of no concern; your concern with foil on secondary is with fruit flies. Take it from me---I found out the hard way. Okay, so it didn't hurt the batch, it actually turned out just fine, but still...you don't want fruit flies in there! If you have fruit flies in your brewery or wherever you're fermenting, just make sure you put that foil on very tight, and poke a few tiny pinholes in the top of it, not big enough for fruit flies but enough to let co2 out.

Agreed with the above. My concern about pressure was based upon the assumption that you would affix the foil to the secondary somehow (rubber bands, tape, etc.).

My infection concerns would be from the fruit itself, rather than the foil. I keep a spray bottle of sanitizer in my "brewery" (aka garage), and quickly spray anything that comes in contact with my beer vessels. Do that and you are fine from airborne or other foreign sources of infection.