Back to Shopping at

Over carbination

I have brewed the Caribou slobber twice. The first time it came out fantastic. This second time around however, the beer tastes off and I think it is over carbed. Does not spew out of the bottle when I open it. However, it is almost impossible to pour into a glass. I have about a half inch of beer and the rest is foam all the way to the top. I did everything the same. I have looked but really don’t have an answer. Anyone want or willing to chime in? I am planning on brewing the oatmeal stout tomorrow and want to make sure this does not happen again. Thanks.

Did you check for final gravity with a hydrometer or refractometer?
How long was the fermentation before bottling?
What was the temperature of the fermentation?
How much priming sugar did you use?
Over carbonation is normally caused by bottling beer that is not finished fermenting, or using too much priming sugar.
Infection can also be a cause.

I had this happen with a porter and it was due to bottling before fermentation was totally complete. Tasted great but was tough to get in the glass.
I feel your pain a bit.



My guess is a slight infection or under attenuated beer. Both would cause what you are experiencing. I would never bottle until 4 weeks after brew day. Also, you have to pay real good attention to cleaning bottles properly.

My most recent batch was also the Caribou Slobber (extract). Mine also was overcarbinated. No bottle rockets but some eruptions after opening or at least mostly foam in the glass. I believe there is one likely cause and one possible.
1. I recently switched from the pre-packaged corn sugar available to using unprocessed (raw) sugar. I used 1/2 cup for a 5 gallon batch. I suspect that may have been too much.
2. I always put the carboy in the fridge the night before bottling. This time however, it was in the fridge for a week before I could bottle it. Plus I had set the fridge temp lower. As a result the beer was about 49-50 deg F when I bottled. Could bottling at 25 deg F cooler than the temperature it conditioned at have caused it to overcarbonate?

OG: 1.055; FG: 1015; Fermintation (ambient) Temp: ~74 deg F; 5 weeks primary (4 at room temp + 1 week in fridge)

1/2 cup per 5gl is not too much. I believe the NB priming calculator would say .6-.75 cups raw sugar depending on the style. I almost always go about 2/3 cup and have not had a problem yet. Be very careful of sanitization with your bottles, as this could cause an infection in the bottle stage and create more carb, and check to make sure you’ve reached FG before bottling.


One issue I noticed early on was that I didn’t have an accurate idea of the TRUE volume of what I was bottling. I was using a carboy with no measurement marks on it so I just assumed it was 5 gallons. One time I transferred my beer to the bottling bucket (and already mixed in the sugar water) I noticed i was bottling 4.3 gallons not the 5.0 I used to calculate my priming sugar. This one came out quite over-carbed.

So in addition to what others said, also be sure you are using the correct volume for priming sugar calculations.

I’ve since added volume markings to all my fermenting vessels.

That’s a good point Matt. Sometimes when I rack to the bottling bucket it’s hard to know what you will end up with.

Don’t want to cause unnecessary concern but I recently recovered from a string of over attenuated/bottle bomb beers. Infections happen less then a new brewer thinks and they are down played because of that. But I know from experience they do happen. My problem developed slowly and took a while to be obvious. I attributed it to things other than infection for awhile. I replaced all plastic and now I’m back to brewing great beers.

However don’t think you automatically have an infection. If your yeast stalled out and started fermenting the rest of the wort + the priming sugar you’ll have a bottle bomb. You can take a gravity reading of the beer after the carbonation is de gased, if its drastically different than what your FG you likely have an infection unless your FG was too high to begin with.

Back to Shopping at