Gusher/Volcano

[BrewerMichel]

Hey!

Having some trouble with beer I keep longer than a couple of weeks. Some of them make small volcano's seconds after opening them. I don't think it is an infection thing because the beer is clear before opening and doesn't taste off.

When I look close it looks like the CO2 bubbles are picking up the thin yeast leayer which results in more bubbles and boom volcano... then the beer is quite muddy because of the yeast.

I prime with 7g/l table sugar.

Any suggestions?

 

[sbaclimber]

Your fermentation isn't done....I sort of have the same problem, but have learned to adjust accordingly.
If / when I forget to save gyle for priming, I will prime with table sugar, 100-125g for ~25 L. After about 4 weeks, the CO2 content is still a bit on the low side, but I like a fairly flat beer, so all good. By about 3 - 4 months in the bottle (generally, very few bottles survive that long), I have to be careful pouring, as the foam has generally reached wheat-beer-proportions by then. Obviously fermentation has continued and the very low amount of sugar can in now way produce that much CO2 alone. But even though I have repeatedly tried remeasuring the FG after X months, but have yet to come up with reliable numbers to prove that much continued fermentation (based on the priming calculator here on brewersfriend)...but it must be occuring, and I do tend to bottle when the FG is where I want it or where fermentation has "mostly" stopped, as opposed to a completely dead airlock.
Weird is, no matter what I do, and no matter how stable the FG has become, I have almost never had a dead airlock, even after 4 weeks of fermentation at room temp + with US-5 and an absolutely stable FG.

 

[BOB357]

The first thing that comes to mind is the possibility that fermentation isn't complete when you bottle. The remaining sugars added to your priming sugar can over carbonate. Are you taking gravity samples 2 or 3 days apart to verify fermentation is done? That's the only way to know for sure.
Other than that and the possibility of infection, you could be over priming if your scale isn't properly calibrated.

 

[BrewerMichel]

Indeed, the older the bottles, the harder they gush. So probably still too much fermentation going on there. Will prime less, and spend some more time in primary or secondary fermentation although airlock was dead last time. Didn't measure FG. Thanks for reply!

 

[BarbarianBrewer]

As mentioned, most likely causes are premature bottling and too much priming sugar. You should use a priming calculator to determine how much sugar (or other agent) to prime with. It will take in how much beer you are priming, what your priming agent is, the style or target volumes of CO2 and the temperature of your beer. The temperature of the beer is important because that determines how much CO2 is currently in the beer. One thing to note is that when it asks you for the temperature of the beer, use the maximum fermentation temperature. This is more important when you cold-crash because of the temperature variance. You should use a hydrometer to know when fermentation is complete. Although if you let it ferment out 3-4 weeks, in the proper fermentation temperature for the yeast strain, you should be good.