5.5 gal into a 6 gal carboy?

I've been using plastic buckets as primary fermenters since I went to 5 gallon batches. The only carboy (glass) I have was gifted to me by my brother-in-law who doesn't brew anymore. It's a 6 gallon carboy. Not 6.5 gallons, which is what I see in all the homebrew stores.

Typically I brew with the intent to end with 6 gallons in my kettle, transferring 5.5 gal to the bucket, hoping to end up with 5 gal to bottle.

If I use this 6 gallon carboy for the primary (soon to be brewing a Founder's Red;s Rye PA clone), am I pushing my luck? The owner of my lhbs gave me a blowoff tube that just barely fits inside the neck of the carboy. I would intend to run that blow off into a 2L erlenmeyer flask with a starsan solution inside. Considering the amount of krausen i've seen in past brews (typically filling the entire headspace inside the 7.5 g bucket, it's safe to say I'd lose a lot of krausen out the blow-off tube. Is this a bad thing? In the past, I've set a smaller diameter blow-off tube on the 3-piece airlock I used for the bucket, but that can get clogged (almost blew the top off when I brewed a 7+% brown ale after the hop matter clogged the airlock and rendered the blow-off useless).

Just wondering if losing a lot of krausen via the blow-off is a bad thing, or if it doesn't really matter.

It really doesn't matter. Some people harvest yeast from the krausen, but there is plenty still in the beer for healthy fermentation. I never stress about krausen flowing out of my blowoff tube into some star san because that just tells me the fermentation is going well and is healthy. I'd say your fine, since you have plans for a blow off tube.

mike20793 said:

It really doesn't matter. Some people harvest yeast from the krausen, but there is plenty still in the beer for healthy fermentation. I never stress about krausen flowing out of my blowoff tube into some star san because that just tells me the fermentation is going well and is healthy. I'd say your fine, since you have plans for a blow off tube.

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Thanks Mike. Just needed a little confirmation. I've been wanting to do a primary ferment in the glass, just to actually see it in action for once. All previous batches have been in the buckets, and I've used the 6 gal carboy for secondary dry-hopping only. Need to get myself a 5 g carboy for secondary use to eliminate the head space in the future.

This is basically my set-up. I start with 7 gallons in the pot (pre-boil) and get a bit under 6 into the carboy. Then I run a large diameter blow-off tube into a gallon bucket with a few inches of sanitizer in it. My first time around, I used the Erlenmeyer flask, but it was too small. I had to empty it.

You will lose some beer, perhaps even a lot, btw. For some people that is an issue. But then some sources suggest that the blow-off set-up is superior (getting ride of certain less desirable materials during fermentation). I'm not an expert on that, so I won't argue for it on those grounds. I'm just mentioning it.

Anyway, If you're going to use this set-up, I'd suggest a bucket, or at least something larger than the flask. That way, it becomes no-hassle/no-worry. Go to work, whatever, don't sweat it (though you may need to keep it away from the cat, if you've got one--don't ask). You can pull off the hose and stick an airlock on there when fermentation calms down a bit.

krahm said:

This is basically my set-up. I start with 7 gallons in the pot (pre-boil) and get a bit under 6 into the carboy. Then I run a large diameter blow-off tube into a gallon bucket with a few inches of sanitizer in it. My first time around, I used the Erlenmeyer flask, but it was too small. I had to empty it.

You will lose some beer, perhaps even a lot, btw. For some people that is an issue. But then some sources suggest that the blow-off set-up is superior (getting ride of certain less desirable materials during fermentation). I'm not an expert on that, so I won't argue for it on those grounds. I'm just mentioning it.

Anyway, If you're going to use this set-up, I'd suggest a bucket, or at least something larger than the flask. That way, it becomes no-hassle/no-worry. Go to work, whatever, don't sweat it (though you may need to keep it away from the cat, if you've got one--don't ask). You can pull off the hose and stick an airlock on there when fermentation calms down a bit.

Click to expand...

I ended up going with the 6 gal carboy for the primary this time. 8 gal preboil, 6 post boil, moved 5 into the carboy. Seemed like a ton of crap at the bottom of the pot this time (more than normal). Not sure if it's because of the grist, or the amount of hops (4 oz pellets in the boil, all loose, no bags). Going to lose a fair amount on this batch, but we'll see what happens. Noticed after the wort had overnight to settle in the carboy, a lot of sediment built up at the bottom.

Used a wide blow-off tube (just barely fit inside the neck) and ran that out to the bucket I've used as my primary in the past, with a good amount of star-san/water solution in it. Pitched the S-05 in the middle of the night (after the carboy had gotten down to 65°) and set it up with a fermwrap and controller set to 67°). Will hopefully get home from work tonight to find it working away. ALL my brews have been in the bucket so I'm looking forward to actually seeing something through the glass with this one.