Over-carbonation after a month in the bottle

[HoosierBootlegging]

So, I have a carbonation problem. I have brewed 6 beers, and 4 of them turned out great. However, two of them (a honey porter and regular porter) were delicious for the first month that they were in the bottle, but then suddenly after that when I pop one open, it foams like a middle school volcano. And it wasn't one bottle, it was the entire batch started doing this at almost the same time, all after about a month.

For both of them I used a calculator to figure out priming sugar, and they both spent a month in a secondary prior to bottling.

Does anyone have any ideas as to what is happening and how to prevent this from happening again?

 

[bu_gee]

Did you verify that the FG settled and was approximately where you expected before bottling?

 

[myndflyte]

Any off flavor that could resemble some kind of infection?

 

[HoosierBootlegging]

The flavor was excellent without any off taste. And the FG had settled, I had both in the primary for 3 weeks and the secondary for a month.

 

[bu_gee]

The flavor was excellent without any off taste. And the FG had settled, I had both in the primary for 3 weeks and the secondary for a month.

I was thinking it might have been a stuck fermentation that let go in the bottle. But that would probably result in broken bottles, not gushers.

 

[bu_gee]

Do you refrigerate your beer before opening them? If so, for how long?

 

[HoosierBootlegging]

I have refrigerated the beer and I have opened it at room temperature, and it does not seem to effect the results.

 

[JayDubWill]

I'm just thinking here, and maybe my thought process is wrong but You could do a little experiment if you know the final gravity at time of bottling by opening a bottle now, let it sit until it's flat (takes longer than you think) then take another gravity reading. If it's significantly lower but still above 1.010~ish then the beer wasn't ready to bottle. If it's low, like 1.003 or lower...it's probably an infection. If it's the same then you probably used too much priming sugar. Notice all the probably's...lots of variables here.

 

[estricklin]

Either your fermentation wasn't complete, or you picked up a wild yeast infection.

 

[bu_gee]

I have refrigerated the beer and I have opened it at room temperature, and it does not seem to effect the results.

Have you allowed sufficient time for the cold beer to dissolve the CO2?

 

[HoosierBootlegging]

I'm just thinking here, and maybe my thought process is wrong but You could do a little experiment if you know the final gravity at time of bottling by opening a bottle now, let it sit until it's flat (takes longer than you think) then take another gravity reading. If it's significantly lower but still above 1.010~ish then the beer wasn't ready to bottle. If it's low, like 1.003 or lower...it's probably an infection. If it's the same then you probably used too much priming sugar. Notice all the probably's...lots of variables here.

Interesting and very clever trick, I will take those readings tonight and see what it says.

 

[HoosierBootlegging]

Have you allowed sufficient time for the cold beer to dissolve the CO2?

What would sufficient time look like? I usually keep a few bottles in the fridge for when the moment strikes, so they could be in there for a few hours or a few weeks.

But I haven't done anything differently than I did on the previous batches which didn't over-carbonate.

 

[bu_gee]

I'm just thinking here, and maybe my thought process is wrong but You could do a little experiment if you know the final gravity at time of bottling by opening a bottle now, let it sit until it's flat (takes longer than you think) then take another gravity reading. If it's significantly lower but still above 1.010~ish then the beer wasn't ready to bottle. If it's low, like 1.003 or lower...it's probably an infection. If it's the same then you probably used too much priming sugar. Notice all the probably's...lots of variables here.

Excellent thought process. Though, I don't think you have that many variables. 1. Is the current gravity the same or lower than the FG. 2. If lower, then is it below 1.010?

It might not give you your exact answer but it can rule out a lot of things.

 

[brewmadness]

I've had foamy gushers with a couple bottles of the several hundred I have bottled. The instances that this happened, when inspecting the bottle I noticed where something was stuck to the inside of the bottle. I'm thinking the bottles weren't completely clean, and therefore not sanitized resulting in some sort of infection in said bottles. I carefully inspect all bottles before bottling now. if anything looks out of the ordinary I will scrub it with a brush....if that doesn't work it goes in the trash. Not going to mess with dirty bottles any more. So....my advice would be to be diligent with bottle cleaning and prepartion. Not saying your weren't, just speaking from experience!

 

[bu_gee]

What would sufficient time look like? I usually keep a few bottles in the fridge for when the moment strikes, so they could be in there for a few hours or a few weeks.

But I haven't done anything differently than I did on the previous batches which didn't over-carbonate.

The common mantra appears to be 3 days.

Are you using the same bottles in this batch as you did for the previous batches? I would say that gushers are less about over carbonation and more about unwanted nucleation. One of your previous batches of beer may have left deposits on your bottles.

There is an easy test for this: pour diet coke in your bottle. If it looks similar to your beer, you've probably got some nucleation sites in your bottles.

 

[HoosierBootlegging]

Some of the bottles are the same, but other bottles were used in different batches without any problems. I will definitely try the diet coke test (if nothing else that sounds really cool!), but would the unwanted nucleation wait several weeks before starting? The delay is what is the most puzzling part!

 

[Qhrumphf]

As far as time in the fridge, it really doesn't take all that long, a day at the most, probably more like a few hours, enough to chill the whole system down to make sure that CO2 stays absorbed in the beer rather than released suddenly.

Primary suspect would be infection. In addition to specks of dirt in improperly cleaned bottles, I had that problem sporadically at first until I started taking apart the spigot of my bottling bucket and cleaning it before bottling every single batch. Lots of cracks and crevices for dirt (and resulting bacteria) to hide in there. There are certain microbes (yeast or otherwise) that can cause gushing infections with little effect on actual flavor.

Another possiblity is calcium oxalate AKA beerscale. If your calcium level in your water is low, it can cause calcium oxalate precipitation which can create nucleation sites for CO2 resulting in gushing. For that reason, any beer I brew I try to have at least 50ppm calcium in the brewing water. What the threshold is for calcium oxalate problems below that, I don't know off the top of my head.

 

[BrotherBock]

Maybe the introduction of simple sugar got the yeast excited again and got them to finish fermenting. Perhaps the yeast got tired a couple gravity points from terminal and the easily digested sugars got their metabolisms going again.