KaBOOM!!

Background: 1.128 OG Belgian/English Barleywine with my first 4L starter. I was already nervous about this brew: https://www.homebrewtalk.com/f12/critique-my-recipe-please-358847/

I last saw it just start bubbling a little before I went to bed around 230-3am last night and when I went downstairs this morning at 8, I saw the carnage. The part that made my stomach churn was that I'm in the middle of battling a fruit fly infestation in my house.

I washed and sanitized the bucket lid, removed the airlock and clipped the tip (I clipped all the other ones I own, I don't know why this one got missed), skimmed the top with a sanitized spoon hoping any fruit flies didn't get past the top foam layer and sealed it back up.

The part that blows my mind is this is a 4.25gallon batch in a 6.5 gallon bucket and sometime between 8 and 13 hours after pitching it blew the lid. I don't use blowoff tubes unless I'm using a carboy because those force everything up into a small area creating more pressure to blow the top. I've never even popped an airlock out let alone blow a lid off a bucket.

I'm really hoping with how vigorous that fermentation is, that the fruit flies didn't contaminate the brew but only time will tell...

That sucks, the krausen probably kept all the flys off and at least you aren't this guys above. I like to reference this video whenever I can. It's awesome.

I have to ask, sitting out like that, what was the fermentation temp?

Blow off tube to start! EVERY time!

air locks will do that.

Check my post I just made in this forum. I am afraid of the same thing and I have a blowoff tube. I am using the same bucket as the guy in the imperial stout video too! It has a great seal but that's what I'm worried about now.

I started my ferm too warm I think, just praying we are not awoken tonight to the sound of an explosion...

Next time I do a big beer like this I'm going to ferment in a 6.5 gallon carboy with a 1" blowoff vs the small hole in the bucket lid...

Basement is pretty much a constant 64 year round. Even with a vigorous fermentation like this, it rarely breaks 74-75f. Usually they're between 68-72. I've never had any issues as far as I can tell with fermentation. Maybe I'll get on board with temperature controlled fermentation someday but I've got a lot of other things that are higher priority to me. If the beer was turning out crap, I'd give it more consideration.

The high gravity stuff can really make the yeast go crazy. You're lucky it didn't cover the ceiling, but it does seem like you had a strong ferment. Guess your starter worked out ok.

Yeah definitely NO problem with the yeast viability, the starter (and my new homemade stir plate) was very effective!

The upside is I'm tasting and smelling the foam pouring out and it's definitely a Belgian! Just worried how much beer I will lose to the geyser.

YMMV, but I've had three blowoffs in the last year and none were contaminated. Two occurred in a basement that's unfinished and both times were under the stairs. The other happened in a closet.

The one that happened in the closet scared my dog quite a bit. She was in her crate when I got home that day and was timid to come out (she is normally at the door greeting me).

But, infection...it kinda depends but many folks here have experienced blowoffs with no problems, so anecdotally you may be fine. Since you actually bothered to sanitize your lid, which I didn't do, I'm betting you'll end up fine.

Yeah I sanitized the lid well. Just checked and it's subsided enough so I put it back in my freezer with the blowoff tube. There's a steady bubbling in the growler but not seeing anymore foam. When I picked up the bucket it felt lighter, will be interesting to see how much beer I lost.

I'm going to get a primary carboy, I only have a 5 gallon right now, for my next high gravity batch. Will avoid any issues like this with a 1" tube and no lid to blow.