How to avoid blowoff on a 1 gallon jug?

Question

I'm experimenting with 1 gallon batches, and every single time I had a blowoff. So for the batch I brewed today I just put a bucket of sanitized water and a blowoff tube to start with since I know that it'll blowoff while I'm at work otherwise.

The recipe kit says to use half a pack of yeast, but even if I go below it I have Kräusen climbing out of the jug.

Is there any harm in this and having a blowoff tube for the first 24-30 hours? Is there any way to avoid blowoff completely without sacrificing the beer? (These 1 gallon batches are mainly for experimentation anyway, but they should still be good, drinkable beer)

I guess I could try to find 2 gallon jugs just so that I have plenty of headroom?

Answer 1

You essentially have four options:

1) Use a blow off tube.
Advantage: Easy to do.
Disadvantage: You risk losing some beer.

2) Find a bigger vessel.
Advantage: No beer lost.
Disadvantage: You need to find a bigger vessel.

3) Use a foam suppressor like Fermcap.
Advantage: You'll lose less beer than with a blowoff.
Disadvantage: Some people don't like using chemical foam control for various reasons.

4) Make less than one gallon
Advantage: You'll be less likely to have blowoff.
Disadvantage: You'll have less beer anyway.

Any of the options are fine. It's just a question of what is more convenient for you. The quantity of yeast you use should not generally have a significant impact on foam production.

Answer 2

There is no harm on having the blow off tube. You could use it during the whole ferment If you want.

As for avoiding it, the only ways are to use a bigger vessel as you said, or make less beer.