Using a blow off tube...

What does everyone recommend? Should I use a 5 gallon primary fermenter with a blow off tube or use a 6.5 gallon with an air lock?

I'd use a blow off tube even with the 6.5g fermenter. I have yet been able to determine when something will foam like crazy. I have a 6g Better Bottle carboy and my blow off tube setup is a 3/8" hose/stopper combination and even THAT was clogged by some thick foam once. Of course the next batch didn't even blow any foam.

For me, it's better safe than sorry.

Even with a 6.5 gal fermentor there will be times when you will still need a blow off tube. Most people use them all the time in the begining just in case. Then switch to an air lock.

My latest batch refused to be contaned by an air lock, so I had to switch over to a blow off tube. It was fermenting at a high temp, so I placed it in a bath to cool it, then took my syphoning tube and put it through the hole in the lid and the other end in the bath. Worked great. The tube was a little snug going in, but worked out really well.

I would not recommend using the 5 gal fermenter for a 5 gal batch. I suspect you will loose lots of volume with all the blow off.

Use a bigger fermenter like a 6 or 6.5 gal. Even with those you may need a blow off.

I use the 6 gal better bottles. I start fermentation with a blow off. 90% of the time I need the blow off. I like to use the orange carboy caps. I attach a plastic tube to one of the outlets on the carboy cap and put the other end in a bucket of star san. Works great. When fermentation subsides I switch to a stopper with a regular 3 piece airlock.

6 gallon with a blowoff, especially for bigger beers.



-Joe

I would recommend Fermcap-S so you most likely won't have to ever deal with a blow-off.

PseudoChef said:

I would recommend Fermcap-S so you most likely won't have to ever deal with a blow-off.

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It depends on the yeast strain. I learned this the hard way on my last batch. 10 drops of Fermcap in the fermenter did nothing to contain the Wyeast 3787 I pitched. I even dropped in more once the krausen climbed up to the airlock and it would not subside.

PseudoChef said:

I would recommend Fermcap-S so you most likely won't have to ever deal with a blow-off.

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and then use a 5 gallon fermenter?

I think I would still want a 6 gal fermenter. When you siphon you always leave some crap in the carboy. So to finish with 5 gallons in the keg you need 5+ gallons in the carboy. Get the 6 gallon fermenter so you have extra space for the eventual bottom of the carboy crap. The 5 gal fermenters are best for long term secondary where you want to reduce the oxygen contact.

EvilGnome6 said:

It depends on the yeast strain. I learned this the hard way on my last batch. 10 drops of Fermcap in the fermenter did nothing to contain the Wyeast 3787 I pitched. I even dropped in more once the krausen climbed up to the airlock and it would not subside.

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is that the weizen yeast cause that stuff goes ape ****.

maida7 said:

is that the weizen yeast cause that stuff goes ape ****.

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It's the Trappist High Gravity Belgian strain. The krausen will look totally normal for the first day or 2 and then suddenly all the yeast tries to crawl out of the fermenter. It even tried to blow off in my starter:

Yep, 6.5 & blow off tube as needed. My first two batches (IPA & APA)did not need a blow off tube & I got by with just an airlock. Batches 3&4 (Raspberry Wheat & Porter) both needed a blow off tube. All in a 6.5 carboy making 5 gallon batches.

maida7 said:

and then use a 5 gallon fermenter?

I think I would still want a 6 gal fermenter. When you siphon you always leave some crap in the carboy. So to finish with 5 gallons in the keg you need 5+ gallons in the carboy. Get the 6 gallon fermenter so you have extra space for the eventual bottom of the carboy crap. The 5 gal fermenters are best for long term secondary where you want to reduce the oxygen contact.

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Yeah, it depends on the actual volume size of the fermenter. My "5" gallon fermenters hold about 5.5 gallons, so I fill up right below the neck and use some Fermcap. Have a bitter in there like that right now - kegging tonight.

Is there a reason for switching out a blow off in favor of an airlock once fermentation subsides?

craven_morhead said:

Is there a reason for switching out a blow off in favor of an airlock once fermentation subsides?

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For me it's so I can move it more easily to a warmer location. I do the initial ferment in the cold basement to keep the temps under control. Then I move it upstairs and warm it slightly to get full attenuation.

Also, the blow off bucket is nasty. Not sure if it would be good to leave that funky mess connected to your fermenter for a long period of time.