I have a problem, that has been pestering me for some months now. My beer gushes from time to time. For example, in one batch i have some bottles that will gush very quickly, some slowly and others not at all. The taste in all bottles is as it should be. No offlavours etc.

I sanitize everything with starsan. Bottles are placed on copper tubes, through which starsan is pumped. I dont think i over prime. The amount of table sugar is calculated is Beersmith, which is then boiled with water for sterilisation. When i mix the solution with beer, I usually mix it for 30-60 min so the solution is really homogenous. Usual batch size is 50 liters.

Do guys have any experience with such problems and what was the solution to them.

I was reading, that malt can be infected with fusarium fungi, which produces protein called hydrophobins that causes gushing. I checked the grains and none have any symptoms of the infection.

Thanks for any answers. Cheers!

  • DId you wash the bottles before sanitizing them?
    – brewchez
    Commented Mar 13, 2017 at 10:39
  • Of course. They were new. Straight from the shop.
    – Razmooo
    Commented Mar 13, 2017 at 10:40
  • How do you measure the sugar? I was totally confused by the need to switch from measuring by volume to measuring by weight.
    – uSlackr
    Commented Mar 17, 2017 at 17:04
  • By weight of course. I use the calculations from BeerSmith.
    – Razmooo
    Commented Mar 17, 2017 at 17:05
  • I just wanted to know if you have been able to resolve your problem! I've had the same issues since I started homebrewing. I've tried many things, but the slow gushing issue stayed. Eventually, I narrowed down the cause to three things: - hop debris in the bottles - too much yeast/sediments in the bottles - too much priming sugar I'll try to improve on these three things and keep you updated. Cheers Commented May 14, 2018 at 5:56

3 Answers 3


If you're completely certain about everything else, about all that's left is incomplete fermentation. Is that a possibility? Although that would tend to affect every bottle. I think I'd have to got with either contamination despite your efforts.

And why do you bother mixing the priming solution so long? A minute or so shoule be more than adequate.

  • Fermentation is complete everytime. Usually i mix for more homogenous solution, so there arent bottles that arent under or over carbonated.
    – Razmooo
    Commented Mar 13, 2017 at 10:40
  • yeah, but a minute or so is plenty for that. I guess there's a slight chance that by mixing so long you could possibly be picking up contaminants.
    – Denny Conn
    Commented Mar 13, 2017 at 16:11
  • I checked the grains yesterday. Some of them had black spots on them and seem like they dried up. I think that mold is the cause for gushing. Will try buying new malt from castle malting. I will post the results.
    – Razmooo
    Commented Mar 14, 2017 at 9:53

I had some beer bottles where a lot of hop fragments had made it to the bottle. The extra surface of the hops made the bubbles start of the yeast and hops in the bottom. The bottom derbies would start to get disturbed by the bubbles and mix into the beer creating more surface area that bubbles could form on... beercano.

This was a high gravity beer with oaths added for extra mouth feel. I did taste the remains of the beer no other off flavor than a lot of yeast due to that mixing in.


I feel like mold would be killed during the brewing process, so I'm not sure that's the root cause, though your malt should probably not have black spots on it ;).

I used to have this problem as well, although not since I switched to all-grain, and also not since I started filtering my water before using it. I've gotten advice from a friend who employs a master brewer that high iron content in the water can cause gushing.

The only other thing I can think of barring incomplete fermentation is what ElvishPriestly said, which is lots of sediment in the bottle.

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