Add blow off wort back to fermenter?
 

Just experienced my first violent fermentation. I've lost 1.5 gallons out the blow off into a bucket. Can the blow off wort be put back into the fermenter? What if that blow off wort is reboiled first? Bad ideas?

My opinion would have to be no.

In practice, the other end of your blowoff tube should be in submersed in a solution of sanitizer, therefore you now have a bucket of some semi-fermented wort and a bunch of solution.

Definitely not! How much headspace did you have in your fermenter?

You should read up on a Burton Union System. I think there is a thread here or an article at BYO that talks about how to make one for home brew. Essentially it is a closed blowoff system where the yeast and foam is captured and the wort allowed to trickle back to the fermentor.

mbauer - very cool, guess this is my new bit of knowledge for the day!

http://byo.com/stories/projects-and-equipment/article/indices/20-build-it-yourself/354-build-a-burton-union-system-projects

Or you could avoid all that hassle and just let it go. It does suck losing beer but that should not be added back. The question is why did you have a blowoff and how can that be prevented? I like to start my fermentation on the cool end of the spectrum to slow down some of the really intense fermentation. Doesn't always work but it helps.

Blowoff was 3/8" tube in a quart jar half full of sterile water, sitting in a 2.5 gallon bucket. Its a IIPA (OG=1.095), distilled water, 9# extract, 2.5# grain, Safale04 yeast, 5.5 gallons in 6.5 gallon carboy. This is the second time to do this same recipe, first time I had no problem. I also dry hopped 2 oz of Goldings in the primary. Fermentation temperature was 66F.

Next time, I plan to wait to dry hop (they clogged the tube), and use Fermcap. And build a closed blowoff recirculation tank.

So much to learn. :-)

Wow, that must have been an active fermentation to lose so much beer with 1 gal of headspace. And yes, I would recommend waiting until after primary fermentation is nearly complete to dry hop, say after 5-7 days. Jamil has said that the CO2 can scrub some of the hop aroma out with it.

Would it create off flavors if I do add it back?

I'm not sure, but you'd be adding sanitizer directly to your beer (wouldn't be "bad" since its safe to drink), but you'd be diluting it and also raising the chance of infection since that still fermenting wort that overflowed was exposed to the air. Just suck it up and have less beer.