From the HBD Archive
From: Martin A. Lodahl <hplabs!pbmoss!mal>
Subject: Blowing it Off
Date: 1990-04-18 16:35:37 GMT

In HOMEBREW Digest #401, Russ Gelinas is considering going to closed
fermentation, and has a few questions:
" ... I'd like to try a closed ferment (is this the same as the

That depends on the size of the batch, relative to the size of the
carboy. If you're brewing 5-gallon batches in a 7-gallon carboy,
it's a rare recipe that will produce enough foam to fill the
remaining volume.

"Papazian says to pitch the yeast in the carbuoy, and then seal
it with a water seal, but then where does the blow-off take place?"

In effect, the blowoff tube is a kind of water seal. While one end
is attached to the carboy, the other is under water in a suitable
receptacle (large jar, jug, pail, etc.). How large this is depends
on how much of the wort you expect to waste in this fashion. I use
a gallon jug, but a couple of times it hasn't been enough.

"If you ... put a blow-off tube instead, when *do* you seal it?"

I usually exchange the blowoff tube for the bubbler when the head
begins to fall. That can be as soon as two days after the start of
fermentation, or as late as a week, depending on weather & recipe.
I've heard tales of infection beginning in the blowoff bucket and
traveling up through the tube to spoil the beer, so I don't like to
leave the tube in place longer than necessary.

I should add at this point that though I'm convinced of the benefits
of closed fermentation, I'm not convinced that a blowoff tube is the
best answer. Sometime in the future I plan to try a 7-gallon

Keep brewing!

= Martin A. Lodahl Pac*Bell Minicomputer Operations Support Staff =
= pacbell!pbmoss!mal -or- mal@pbmoss.Pacbell.COM 916.972.4821 =
= If it's good for ancient Druids, runnin' nekkid through the wuids, =
= Drinkin' strange fermented fluids, it's good enough for me! 8-) =

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