What causes gushers?

[noshadow]

I recently followed a Coopers recipe for an IPA using their Brew A kit, LME and Mangrove Jack's M42 yeast plus dry hopping five days before bottling. My OG was 1.042 and FG 1.010 so by my calculations this gives 79% attenuation so falls perfectly withing the yeasts range of 77-82%. FG readings were spread across three days to make sure it was stable. Once done it was bulk primed at 2.5 vols of CO2 and stored at the same temp it had been fermenting at.

Two weeks after bottling I put the rest of the bottles in the coolest place I could find in the house, so probably ranging between 15-17. I took one bottle and put it in the fridge for sampling. When I opened it I had no issues with any beer gushing. I left the rest of the bottles to condition for two weeks and now I've chilled and tried three more bottles but each of these bottles has started to gush just after opening the bottle.

This is the first time I've experienced this so I'm not sure what's causing it. Is it caused when fermentation isn't completed and then the beer continues to ferment after being bottled? Did I over carb the beer? Even if I over carbed it I don't think it would cause this as I've had other brews at a higher carbonation level.

The beer still tastes great and I'm happy with the results, I'd just like to know how to avoid it gushing out in the future.

 

[An Ankoù]

A number of things can cause gushing: sometimes an overattenuative yeast which nibbles away at residual polysaccharides will ultimately overcarbonate the beer, wild yeasts will do this, too. Another issue can be serving the beer too warm. Leave it overnight in the fridge and it should be fine. Particulate matter in the bottle such as debris from pellets used for dry hopping provide nucleation points for effervescence, I had a similar problem with my lager: I noticed that some bottles gushed and others didn't. It turned out to be my bottle cleaning regime- I always pour and rinse and rinse again the next morning, add some sodium metabisulphite solution and recap. While this leaves the bottle sanitary enough for refilling, it was leaving a fine film of yeast crust on the bottom of some of the bottles and this, again, was providing nucleation points for effervescence. It's not enough to sterilise, the bottles also need to be clean and smooth inside. I've read lots of comments here and elsewhere about infection with some sort of dreaded "gusher bug". I'd check everything else first before suspecting infection.

 

[Covrich]

Agreed with alot AA says , I would say I have had two types I woudl say are gushers

1) - absolute fountains which go like mt versuvius - for me these tend to be unique to that bottle so in other words not clean and thats caused the isolated issue, these tend to rip up any bottle trub too.

2) when a batch tends to be overcarbonated and after the initial fizz rather than explode it wants to escape quickly and there is no way it will fit into a pint glass, in these cases I use a 2L jug pour the lot in and settle down, in these cases I think its just a case of it carried on fermenting a bit more and or in some capacity has over carbed, if they are too gassy as a result if that ever happens I just wait for the jug to settle transfer to glass and back and forth you can degas it and have a decent drink

 

[foxbat]

Is it caused when fermentation isn't completed and then the beer continues to ferment after being bottled?

It's most likely accidental contamination with a wild diastaticus yeast strain, or if you've previously intentionally brewed with diastaticus (e.g. Saison, some Belgians, anything by White Labs (joke!)) then it could be insufficient cleaning of the fermenter.

Diastaticus yeasts secrete an enzyme that breaks down the "unfermentable" dextrins that make up your FG at bottling into simple sugars that then get fermented. It's particularly insidious because it happens very slowly, over weeks and months so you think you're safe at bottling then much later you get gushers or bottle bombs.

Deep clean your bottles with a chlorine-based cleaner and replace your plastic fermenter and any silicone tubing would be my advice.

 

[Sandimas]

I get gushers every year this time of year, seems to be a lot worse in the summer months. I think this could be down to storage temperature, I put my bottles in the garage and it gets a bit warm in there. But even so, something must be fermenting away to generate the CO2. I'm ultra-careful that brews are finished, sometime bottling as late as Day28, but I do re-use bottles and wonder if something is staying in the bottles even after washing and sanitising. It's something that has perplexed me for years and I've never got to the bottom of it. I've had "proper" bottle bombs from infections, but this is not like those.

 

[WierdFish]

I had a bottle explode in the fridge during the 2 weeks secondary after bottling, and a couple of the bottles were gushers when i got to drinking them weeks later. The cause? I forgot the stir in the diluted sugar when batch priming, so there was obviously a 'hot patch' in the FV. I realised when I had bottled half of the FV but opted not to tip the bottles back in and start again, for fear of over oxidising. Lesson learnt.

 

[samale]

Can serving temp have an effect. I regularly swap beer on the forum. The last two were gushers that I sent to @Hazelwood Brewery. Really not sure why, this was the first time it has happened. I tried the beer again at home with no issues. I drink all my beer well chilled probably anything between 4-8 degrees I think he may drink his beer at a higher temperature.

 

[Hazelwood Brewery]

Can serving temp have an effect. I regularly swap beer on the forum. The last two were gushers that I sent to @Hazelwood Brewery. Really not sure why, this was the first time it has happened. I tried the beer again at home with no issues. I drink all my beer well chilled probably anything between 4-8 degrees I think he may drink his beer at a higher temperature.

I do enjoy beers at higher temps and probably served these at about 16C?

I would have enjoyed @dave_77 ‘s beers at about the same temp and although his beers were just as effervescent (one at least) they didn’t foam.

There is some chemistry at work here that seems to be holding the gas in a foam. Dave’s beers were clear, yours were intentionally hazy - could it be something to do with the heady mix of high carbonation (rich source of gas) AND high protein (stronger head retention) AND warmer temperatures (greater liquid and gas expansion)?

Disclaimer: I have no idea what I’m talking about here and these ramblings are based on nothing more than pseudo-science!

 

[Mavroz]

If I take a bottle from the garage, remove the cap, after a few seconds the beer tends to bubble out of the top of the bottle.
If I take a bottle from the fridge that has been in there around an hour, the beer doesn't bubble out of the top of the bottle.
They are not gushers or rushers by any account but I do think temperature has an effect when the bottle is opened.

 

[samale]

I do enjoy beers at higher temps and probably served these at about 16C?

I would have enjoyed @dave_77 ‘s beers at about the same temp and although his beers were just as effervescent (one at least) they didn’t foam.

There is some chemistry at work here that seems to be holding the gas in a foam. Dave’s beers were clear, yours were intentionally hazy - could it be something to do with the heady mix of high carbonation (rich source of gas) AND high protein (stronger head retention) AND warmer temperatures (greater liquid and gas expansion)?

Disclaimer: I have no idea what I’m talking about here and these ramblings are based on nothing more than pseudo-science!

16 degrees
That's soup temperature

 

[Hazelwood Brewery]

16 degrees
That's soup temperature

 

[Pennine]

I do enjoy beers at higher temps and probably served these at about 16C?

I would have enjoyed @dave_77 ‘s beers at about the same temp and although his beers were just as effervescent (one at least) they didn’t foam.

There is some chemistry at work here that seems to be holding the gas in a foam. Dave’s beers were clear, yours were intentionally hazy - could it be something to do with the heady mix of high carbonation (rich source of gas) AND high protein (stronger head retention) AND warmer temperatures (greater liquid and gas expansion)?

Disclaimer: I have no idea what I’m talking about here and these ramblings are based on nothing more than pseudo-science!

This has been similar for me. I always pour cold now and let them warm up in the glass. I think its either the yeast on the bottom which causes nucleation points and hence the gushers, some lingering diastaticus, or hop creep. Not sure which so now bottles go in the refrigerator after 1 week of carbonation at room temp. Especially in the summer.

 

[Hazelwood Brewery]

This has been similar for me. I always pour cold now and let them warm up in the glass. I think its either the yeast on the bottom which causes nucleation points and hence the gushers, some lingering diastaticus, or hop creep. Not sure which so now bottles go in the refrigerator after 1 week of carbonation at room temp. Especially in the summer.

I don’t really bottle beers apart from comps and bottle swaps. Everything is kegged, not heavily carbed, and served at sensible temperatures. Bloody lovely!

 

[dave_77]

This has been similar for me. I always pour cold now and let them warm up in the glass. I think its either the yeast on the bottom which causes nucleation points and hence the gushers, some lingering diastaticus, or hop creep. Not sure which so now bottles go in the refrigerator after 1 week of carbonation at room temp. Especially in the summer.

Last year I had random gushers, it wasn't one particular batch of beer and I could have 2 or 3 that would then plenty that wouldn't all bottled at the same time. I thought could have been any of these points..It stopped after i thoroughly cleaned my bottling buckets and Syphon tubes. I also started stiring the priming solution gently through the beer. I used to just Syphon on to the solution and then bottle, I wondered if some of the bottles got more sugar than others. I'm not sure which cured it but the clean and adding the sugar after syphoning to the bottling bucket has solved the issue.

 

[chthon]

In addition to @An Ankoù : a yeast that is a bit slow at the end, and the impossibility to distinguish the final gravity lower than 1 gravity point, because hydrometers are mostly not precise enough, with a scale on the order of two gravity points per measure mark.

But 1 gravity point is about 4g/l of sugar, which can lead to gushers.

I think I have this with MJ 79 Burton Union yeast. I carbonate between 1.5 and 2.0 volumes CO2, but after a while I get gushers. I think that this yeast needs a little more time to finish fermenting completely. And the reason why I think this is the case, is that they are not off-taste, don't develop another (drier) mouth feel, they still taste nice.

If this is the case, most gushing can be avoided by keeping these beers a couple of days in the fridge, to make sure that CO2 has really dissolved, then only taking them out half an hour before serving, and letting them warm up in the glass.

 

[An Ankoù]

In addition to @An Ankoù : a yeast that is a bit slow at the end, and the impossibility to distinguish the final gravity lower than 1 gravity point, because hydrometers are mostly not precise enough, with a scale on the order of two gravity points per measure mark.

But 1 gravity point is about 4g/l of sugar, which can lead to gushers.

I think I have this with MJ 79 Burton Union yeast. I carbonate between 1.5 and 2.0 volumes CO2, but after a while I get gushers. I think that this yeast needs a little more time to finish fermenting completely. And the reason why I think this is the case, is that they are not off-taste, don't develop another (drier) mouth feel, they still taste nice.

If this is the case, most gushing can be avoided by keeping these beers a couple of days in the fridge, to make sure that CO2 has really dissolved, then only taking them out half an hour before serving, and letting them warm up in the glass.

Interesting. I'm getting this with Opshaug kveik, which, after a hearty start, never seems to quite finish. L'allemand Voss, on the other hand, does the job, packs up his tools and leaves the site. Prefer the taste of Opshaug, though.

 

[dwhite60]

I did a stout last year that had gushers. Knew I didn't over prime it. Thought maybe I bottled too early. Thought it might be an infection. I took the time to vent them down and they stayed down.

I pitched this with WB-06. Think I just bottled too early. It had been two weeks but another few days would not have hurt.

I've got a saison in the bottle now I fermented with Belle Saison. Trying to get the bottles extra clean after drinking. They get rinsed well then I hit them with iodophor. Belle Saison will take a beer down to 1.000 so I need to kill it off before reusing the bottles.

 

[samale]

A

 

[noshadow]

Thanks for all the replies, definitely a lot to think about. The gushers haven't been too ferocious at all, it just overflows after a couple of seconds and I'm actually able to pour it into a glass without too much hassle.

I usually give a good overnight oxi clean when I clean bottles, FV, etc. so I'm fairly confident it's not that. I've got a note of which FV I used so next time I use it I'll be able to see if that brew suffers from similar. Maybe I didn't chill them for long enough, so I'll be sure to put the next bottles in the fridge for 24 hours. Quite sure I didn't overprime but I'll be more conscious of mixing when bulk priming in the future. If I use this yeast again I'll put in my notes to maybe give it a bit longer to finish fermentation just to be sure it's done.

 

[UKSkydiver]

I made a porter recently. Half were standard recipe, the other half I added a cold brew coffee solution. I just chucked the coffee solution in the FV for a few days. These are the gushers, which leads me to believe that I introduced “something” that is causing the gushers. As long as I serve cool, be ready with a few large glasses to catch the foam, decant all into a single glass and leave to degas for a few minutes, the result tastes lovely. I will concede, it’s a bit of a faff.