Over carbonation

[Mark Weusten]

My 3 last partial mash beers have all become over carbonated after sitting in the bottle for around 3-4 months ie gushers (good drinking at 6 weeks). Today I looked after sick child so when he slept spent an hour slowly releasing the caps on plastic bottles and letting the CO2 out. I have always followed the 2 drops per 750ml bottle and I only have got this issue with partial mashes. It does work but is a painful process. I guess I didnt let the beer get to FG? They where in the fermenter for at least 2 weeks and no gravity change over the last two days. No off flavours I am confused why this happened....maybe 2 drops per bottle is too much?

[Cain Harland]

I had a bunch like this, I suspected under pitching the yeast so I made a stir plate from old computer parts and started making starters. The couple I have done since are much better.

I assumed for a long time that the yeast would just multiply and do there thing and at worst you would just have to leave it a little longer. But it seems not or at least not always, sometimes it doesnt ferment completly and keeps on fermenting very slowly for months also you can get off flavours from the yeast working too hard. I got away with it for a while but now a whole bunch in a row have seemed alright for a while then turned into fiz bombs, some ok just over carbed, others with off flavors, and the hoppy ones losing their hoppy goodness.

The conical flask was about $30 but the rest was mostly free so a good investment. The beer is tastier, cleaner (oddly less yeasty for having more yeast), clearer, not over carbed and keeps better.

[Mark Weusten]

Could well be. They were all around 1060-1055, finishing low and I only used one packet of various dried yeasts. I am harvesting yeasts now and doing big pitches so hopefully wont happen again.

[Chris]

I agree.

You need to make sure the yeast is going to be ready for the environment and has enough cells to do the work so it doesn't try do the work during what would normally be the conditioning phase.

You can work this out by taking good brewing notes and working out your lag time, time before high krausen (sp?)

A cup of slurry should be pitched for wort over 1.050 if you are harvesting yeast.

You can also rack off to a secondary and leave it for longer in the carboy so it cleans up after itself.

7 day primary 14 days secondary 7 days aging is my normal fermentation profile for ales.

[Sam DT]

I'm starting to have this problem with three of my AG brews which I brewed at the end of June. Had two gushers and one that was clearly over-carbonated in the past week. Up until now they've been tasting great but something seems to be going wrong. Fortunately I've only got a few bottles of each left so not a big loss but not ideal...

Used WLP 001 with 4L starter split for the first two and a 1/2 washed cake re-pitch on the third, well oxygenated, 7 days at 19-20 followed by another 7 ramped up to 23 deg - maybe I need to add another week here?

All the bottles were soaked in bleach for a week and then triple rinsed and sanitized.

I used the same batch of yeast across all of them, wondering if I got a slight infection in my initial starter which is kicking in now the temperature is rising in my laundry? Other option could be my bottling bucket and siphon tubing but I soak in per-carbonate for at least 20min before bottling...

I've got my split 001/007 epic PA clone which I'll be bottling next week so that might provide some insight in a few months time as to whether it's a yeast issue - although it'll have had three weeks in the primary as well due to the 10 day dry hop schedule

[Mark Weusten]

Sounds like you are not over pitching and sanitary conditions good. Puzzling...

[Chris]

Are all the bottles gushers or just one or two? (Infection or over priming of individual bottles)

Do you rack off to secondary? (So not as much yeast is transferred to bottles, more time to condition)

What do you use when bottling, sugar wise, might be over priming the bottles. (CO2 levels can be calculated based on temp etc)

You can also cold crash to ensure they don't turn into gushers if you monitor them early on and put them in the fridge early. (Hibernate the yeast)

Hope some of those ideas help ya.

[Sam DT]

Hey, cheers for the ideas.

I've now had about 3 gushers and 2 well over carbed beers in the last two weeks in total (I wrote the first one off as random but getting a bit of a pattern now). The previous 25 odd bottles of each batch were all fine.

I bulk prime using dextrose, with these batches I used 130g across 23 ish liters bottled aiming for carbonation level of 2.3 volumes - used a calculator for temperature correction.

I don't use a secondary or cold crash before bottling but am currently doing my first cold crash (along with a different yeast & an extra week in primary) so maybe this'll get me over the line.

My laundry is just starting to nudge up to around the mid teens where over winter it's below 10, I'm wondering if the temperatures may have suppressed any infection or over zealous yeast issues but now the temperature is rising these might be coming out of the woodwork...

I'll see how this batch goes - otherwise I might have to start clearing the fridge - not sure the wife would be into a laundry to cold store conversion...

[Cain Harland]

Another possibility is temperature control. Maybe the its too cold and the yeast are being a bit lazy in fermenter leaving more fermentable sugars to slowly eat in the bottle. After a discussion on here I moved the probe for my stc-1000 from any random place in the fridge to inside the base of my converted 50L keg fermenter (in a thermowell would have been better but where it is there is very little air circulation and its right under the beer so its effected as little by the air temp and as much by the beer as it could be without cutting holes in the keg). Any way I noticed after doing this my 25w light bulb that I was heating the cabinet wasn't cutting it any more in the cold of winter so I swapped it for one of those little low wattage panel heaters that you can put in a linen cupboard. So the only conclusion I can draw is the light bulb was heating the surrounding air to temperature but not the beer. I was defiantly under pitching too but I think maybe I was getting away with it in warmer weather then being punished when the colder weather made the yeast lazy.

[John H]

I have had an issue once with a poorly mixed bulk prime, which resulted in a few bottle bombs in the hot water cupboard, some drying washing that smelled like beer and one mega-un-impressed wife.