Enough space to not need a blowoff?

[gingervitis]

Just got an old glass carboy from my girlfriend's uncle from when he used to brew ~15 years ago. Question is, do I have enough room for foam to not need a blowoff tube? Its about 6.5-7 inches below the stopper where the 5-gallon line is (I highlighted it in photoshop with a green line). I like to brew porters and stouts, and I hear higher gravity beers need more room for foam in the primary, is that true? Here's a pic:

 

[MRbutlertron]

It can never hurt to throw a blowoff tube on there. I would say just put one on if this is your first batch in a while and see how it goes, then play it by ear from there.

 

[gingervitis]

You're probably right, can't hurt. Do most people use tubing attached to a stopper, or tubing that fits snugly inside the opening of the carboy?

 

[Ravenshead]

I use a 6.5 gallon carboy for 5 gallons batched and still get blowoffs on almost every other brew. There's no such thing as enough head space to avoid it. I just don't worry about it much since I ferment in the garage.

 

[o4_srt]

You're probably right, can't hurt. Do most people use tubing attached to a stopper, or tubing that fits snugly inside the opening of the carboy?

Snug tubing that fits in the opening. Smaller tubing can potentially clog, sometimes leading to wet ceilings.

 

[gingervitis]

How long should a blowoff tube be left on a primary?

 

[TTB-J]

How long should a blowoff tube be left on a primary?

Until active primary fermentation is done, which is generally a few days if you pitched the right amount of yeast and have a good temperature. It will likely be pretty obvious - once you see the krausen starting to come down, you'll know it's fine to swap out the blowoff tube for an airlock.

 

[gingervitis]

Awesome, thanks for all the help guys.

 

[Rockape66]

You don't really have to change from a blow-off tube to an airlock. The blow-off set-up is in effect an airlock. If you want to do so; if not don't.

 

[pjj2ba]

I ferment almost exclusively in 5 gal. carboys and almost never use a blow off. I fill my carboys quite full too. I do tend to ferment on the cool side, plus I use FERMCAP. It does a great job at limiting foaming during fermentation (and boiling if you have foam over issues)

 

[gingervitis]

I've heard about Fermcap, obviously you don't notice anything bad that it's contributing to your beer if you always use it, right?

 

[jwplessner]

I use silicon drops but still get blowoff in my 5 gallon carboy, albeit milder. Its food grade stuff, safe in small amounts, and sinks into the.trub once fermentation settles down.