How do I prevent blow off

the easy way to eliminate popping the airlock is to simply not use an airlock. problem solved.

some people fix a length of tubing over the carboy opening and place the other end in a bowl of water. i just place a piece of foil over the top. more likely i use a bucket and place the lid loosely over the top. you only need to keep critters out, the risk of wild contamination is very slight if you handled your wort carefully.

if this is beer in a secondary, then you should use an airlock. and there shouldn't be any blowoff in that situation anyway.
Cheers.

 

The answer depends on your set-up. If you ferment in a bucket, then you need to convert your air lock to a blow-off tube arrangement. You need to get some plastic hose (3-4 feet) that will fit over the center stem of the air lock and then run the other end of the plastic tube into a container of water that sits next to the fermentor. You might also want to clip off the tiny pieces of plastic at the bottom tip of the center stem so that the plastic barriers don't stop the flow of the krausen bubbles.

If you use a carboy (a 6.5 gallon is recommended for primary fermentation of a 5-gallon batch) then purchase 3-4 feet of plastic tubing that will fit into the mouth of the carboy, and then place the other end in a container of water. If the tubing is not tight at the mouth of the carboy then wrap some plastic warp around the tubing before jamming it into the hole.

 

Use a larger fermenter. The more head space the less likely there will be blowoff.

Or brew a smaller batch.

 

I use a larger fermenter (7.9 gallon plastic bucket).

You could also use Fermcap to manage the amount of krausen; a few drops per batch keeps the level of krausen down.

The solution of a blow off hose was already discussed.

Cheers!

 

I'll second ferm cap. It was always a gamble leaving a fermenting carboy while I was at work. Haven't had any mishaps since using it.

 

Most of the suggestions have been made. However, I'll add that if you don't use an air-lock or blow-off tube, and just go with foil or loose fitting lid...make damn sure you don't have any fruit flies in the house. They love wort, and so does the lactobacillus that they harbor.

 

Ferment your beer cooler and that should prevent the blowoff. Cooler fermentation temps slow down the process and prevent the blowoff, and usually (depending on the yeast and style)produce cleaner tasting beers.

 

Use a blow off tube.

Leave enough headspace in a PROPERLY sized carboy/bucket.

Control the fermentation temp.

If you use the bottom two suggestions, you might could avoid a blow off tube. I'd suggest one if you have any inkling that it will get close.

 

I use some 3/8 stainless tubing bent in a u that I use as a blowoff wand if you will. One end is shorter and goes into the bucket or carboy bung, the longer end goes into a growler. I also use a vinters harvest bucket as it is an 8gallon bucket, and I ferment cool. Once the initial vigor of the fermentation ends I ramp my temp up a bit to keep the yeast working. All of this happens within the specified temps for the yeast I am using of course.

 

Definitely go with a blow off tube and make sure you have enough head space in your carboy