I have so far used a blow off tube on a 5 gallon fermenter for primary, and there sure is a lot of foam and hop resin in the tube by the end of primary fermentation. I also seem to lose over a quart of beer. I hear that some home brewers start out with a 6 or 6.5 gallon fermenter for primary and then rack to a 5 gallon for secondary. I would imagine there would be some blow off but much less. Any issues with harsh hop resin bitterness in the finished beer as described by Papazian? Is all this blowing off overrated and a waste of beer, or does it have merit? Thank you.
Use a bigger fermenter if for no other reason is to make cleanup easier. My favorite is a wine bucket I think mine is 8gal and I never deal with blowoff and it’s a snap to clean.
I use a 6.5 Gallon Carboy and a 7.9 Gallon Speidel fermenter as my primary vessels. When I do secondary, I use 5 Gallon Carboys and they usually fill up right to the neck, reducing exposure to oxygen. Only one time with the Speidel did I need a blowoff, and that was a German Dunkelweizen that had some wheat in it.
And remember, you’ll seldom get vigorous blowoffs if you control your fermentation temps at the lower end of the yeast’s temp. range. And usually get fewer off-flavors as well(there are a few exceptions-thinking US-05).
My latest example was a Notty that I pitched to an Irish Red. On day 2 the temp rose to 70 and she blew, to the point that I had to add a blowoff tube. Pitched that same Notty to a Robust Porter and controlled the temp in the low 60’s. No blowoff. The Red has some esters- not obnoxious, but noticeable. The Porter is clean.
Edit- my fermentation buckets are 6.5-7G. Carboys are 5G. Past couple years have used the carboys only for lagering or extended cold conditioning(altbiers)
There is no advantage to having blowoff. It does push harsh resinous flavored gunk out of the beer, but that gunk would sink to the bottom or be stuck to the sides and be left behind in the fermentor anyway, so having blowoff doesn’t improve the finished beer. Papazian wrote that a long time ago and understanding of how things work in homebrewing has advanced since then.
Use a bigger bucket to keep everything clean (as Brewcat suggested) and keep the fermentation temperatures down (as Jim recommended) and you won’t ever have to worry about blow off again. And more importantly, with lower fermentation temperatures you’ll get better tasting beer.