Top blew off the primary

[Bradfordmon]

Making a Dunkelweizen using malt extract and a grain bag. White labs hefeweizen ale yeast. Finished it at 10p and went to sleep. Checked it at 6am and the top of the CO2 vent had popped off so I replaced it. Got home from work and the whole top had blown off of the bucket. What happened?

 

[freisste]

Krausen plugged it and the co2 from the yeast caused a pressure buildup. Try a blowoff tube in the future (a tube leading into a jar of sanitizer).

 

[xmacro]

Pics or it didn't happen

 

[Andromedus]

I had the same thing happen with a WYeast 3068 Hefeweizen nine days ago. The foam plugged up the one-way valve, which caused a pressure buildup. I was using a glass carboy, the top blew off so violently that the valve broke into two pieces when it hit the ceiling and the rubber stopper flew another direction, taking me 20 minutes to find. I had wort all over my ceiling. I had an identical 5 gallon carboy next to it with no problems, but it had .5 gallon less liquid (5.25 instead of 5.75 gal). The bottom line is that you over-filled your fermenter (most likely) or may have done something to excite the yeast excessively (doubt it). I would double check the dimensions on your fermenter and make sure you didn't have more than 5.25 gallons in there. I wouldn't toss the baby out with the bathwater, keep the beer and see how it goes!

 

[YeastHerder]

Anything I brew with WLP300 (hef strain), WLP320 (hef strain), or WLP530 (abbey strain) does this. These strains seem to just get more foamy than others. Just search for blow-off tube and its a pretty simple solution. After the first couple days of the really active fermentation pass you can slap the regular airlock in place.

You may also want to look more closely at your fermentation temps, its probably warmer than you think or want.

 

[kylevester]

Three times this has happened to me. Amazingly it didn't happen on one where the airlock was overwhelmed three times in the first 3 days. I thought it was done after the second and ignored it for a weekend and came home to a very clogged airlock which I replaced again and moved from the basement to the kitchen. There's still a bit of foaming coming into the stem of the airlock. Just a crazy fermentation and the biggest I've ever had.

Anyway, none of the ones I had the lid pop off ended up infected, but as always Your Mileage May Vary. It's dependent on the surroundings and the stage of fermentation thus you may just be ok, I'm not gonna guarantee it though.

To fix, do as others say and use the blow-off tube method.