Why am I always attaching blow-off tubes?

Hi everyone. I'm currently on my fifth home brew batch, each 5 gallons. I have been using the 6 gallon plastic paint buckets for brewing, although I just started a brew with my new glass 6.5 gallon carboy.

For the last two brews in the plastic buckets, an Imperial IPA and a Russian Imperial Stout (both high gravity, 7.5-9% abv), I noticed beer and foam entering the airlock between about 24 and 48 hours after pitching the yeast. Both times I attached a blow-off tube, which I submerged into a half-fill growler containing a double-strength iodophor solution. After about a week I removed the blow-off tube and re-attached the airlock with sanitized water. Those beers came out perfectly, nice and clean.

At this moment, I'm looking at an Imperial Nut Brown that I pitched about 25 hours ago, and it's in my new 6.5 gallon carboy. The fermentation began in earnest around the 12-hour mark, and now the foam on top of my beer has reached all the way up into the neck of the carboy, touching the bottom of the airlock. It seems it's only a matter of time before beer and foam will enter the airlock. I have several other home-brewing friends, but none have needed to attach a blow-off tube, and none have reported beer and foam in the airlock. Am I doing something wrong? Or am I just pitching my yeast too well, hah!?

You might want to check your temps. Too high a fermentation temp can do that. Then again, you are brewing some pretty big beers, so it might just be one of those things.

As long as your beer is turning out good (not a high ferm temp problem etc). There is nothing wrong with this.

Could be that you are pitching the 'correct' amount of yeast, well aerated and ready to go compared to your friends.

After cleaning up some messy explosions from stuck air locks, I always use a blow off tube. Even then sometimes with a massively pellet hopped beer I run into problems.

Your friends are probably under pitching. I've needed a blow off tube for nearly every batch I've done, albeit most were Belgians.

Definitely not doing anything wrong (assuming your temps are in control). I have had a dark belgian strong blow off a carboy cap with a blowoff tube attached. Thick krausen plugged the tube, and the explosion was massive. That was fermenting at 65 by the reading on the fermometer.

Just make sure nothing gets clogged, and be happy that your yeasts are happy.

Seems to me that the key word in all your blow-off batches is "Imperial". That means much more fermentables & therefore more yeast activity. My Barleywine was ~4gal in a 5.5gal carboy & still volcano-ed out of the airlock. Blow-off tube = our friend!

Save some beer and buy ferm cap. 8-9% is going to possibly be out of control in any event.

I follow the Mr. Malty pitching rates, and I usually need a blowoff for OG 1.050-60 or higher (or there abouts, no science). Then again I aim for 5.5 gallons in the fermentor.

What is your primary volume? It could be you are putting 5.5 gallons of big beer into a 6 gallon fermentor. In which case, yeah you're gonna have a blowoff. Maybe your friends are ending up with 4.5 gallons in a 6.5 gallon carboy.

At any rate, it's pretty normal to need a blowoff tube for 7.5-9% beers.

Get a bigger fermenter if you dont like it. A wine bucket works great.