Over-carbonation Problem

[cpsmusic]

Hi,

In November last year I did a couple of AG brews (a JSAA clone, and an English Pale Ale). I sampled both brews around Christmas and both were fine and had the appropriate level of carbonation.

I recently tried one of the ESBs and noticed that the bottom of the PET bottle it was in was being pushed outwards pushed outwards so I opened it over the sink and sure enough, it's a gusher. It foams for a good five minutes, and when poured into a glass is clearly over-carbed. The same thing seems to have happened (although to a lesser extent) to the JSAA clone.

The Pale Ale had an OG of 1.053 and an FG of 1.014. It was bulk primed with 83g of dextrose to produce a carbonation level of 2.0.

The JSAA had an OG of 1.045 and an FG of 1.014. It was bulk primed to produce a carbonation level of 2.5.

The bottles have been stored in a cupboard in a non-airconditioned flat in Melbourne.

I don't understand what's happened here. The only thing that I think could have happened is that some additional fermentation has taken place during one of the hot spells that we had over Summer.

I thought that 1.014 would be OK to bottle at especially for the Pale Ale?

The main question I have is, how many gravity points above the expected FG will produce "gushers". For example, if I bottled at 2 points above the expected FG would that produce the problem? That doesn't seem like very much considering the amount of error in reading a hydrometer.

Cheers,

Chris

 

[pcmfisher]

What do they taste like?
Are they clear in the bottle before opening?
Was 1014 above your expected FG?

 

[cpsmusic]

They taste fine. I've made the JSAA before and it's pretty much identical.

Both batches are clear in the bottle. The only indication that something's NQR is that if I put the bottles on a flat surface they won't sit flat because the "bump" in the centre of the bottom is being forced outwards.

For both batches I was expecting an FG of 1.013.

Also, both batches sat in the fermenter for at least a week after fermentation had finished:

For the pale ale:

19/11/11 1.053
21/11/11 1.014
03/12/11 Bottled

For the JSAA:

15/10/11 1.045
17/10/11 1.016
25/10/11 1.014
29/10/11 Bottled

 

[.DJ.]

what was the recipie/ingredients?

 

[malt_shovel]

They taste fine. I've made the JSAA before and it's pretty much identical.

Both batches are clear in the bottle. The only indication that something's NQR is that if I put the bottles on a flat surface they won't sit flat because the "bump" in the centre of the bottom is being forced outwards.

For both batches I was expecting an FG of 1.013.

Also, both batches sat in the fermenter for at least a week after fermentation had finished:

I would be interested to check the gravity of the beer now. Would need to de-gas the bottles and prevent evaporation. It would take some time, but take a bottle, open it and let it spew out some beer, but leave enough for a gravity reading. Periodically open and re-seal as the gas comes out of solution. Once flat (may take days) take a gravity reading. This should shed some light on it. If it is still around 1.014, then too much priming sugar would be a culprit. If it is a lot lower, then suspect a wild yeast / infection.

Cheers
:beer:

 

[cpsmusic]

The problem seems to be a bit worse for the Pale Ale.

What's more, my aim was for it to have a relatively low level of carbonation (around 2.0 volumes) so it's all the more strange as to how it's become so gassy.

I'll try taking a gravity and see what that shows.

I don't think there's been an infection as the flavour seems fine.

View attachment Pale_Ale_IV.pdf

 

[Ross]

The problem seems to be a bit worse for the Pale Ale.

What's more, my aim was for it to have a relatively low level of carbonation (around 2.0 volumes) so it's all the more strange as to how it's become so gassy.

I'll try taking a gravity and see what that shows.

I don't think there's been an infection as the flavour seems fine.

Despite flavour seeming fine an infection taking hold is the most likely answer.

Refridgerate & consume asap if you are enjoying them.


cheers Ross

 

[cpsmusic]

I'd like to understand what's happened so could someone explain how infection leads to more carbonation.

Is a wild yeast able to ferment sugars that yeasts like S04 and US05 can't?

 

[cpsmusic]

Here's a bit more info:

I went through all the bottles and most of the pale ales appear to be OK, however most of the JSAA are "bulging". All up, I think I've got about 15 bottles of pale ale and 5 bottles of the JSAA (I make 20L batches which makes about 26 bottles).

I opened one of the bulging JSAA bottles and it foamed for about 8 minutes. It looks, smells and tastes fine. I've put some in a container and when it goes flat I'll take a gravity reading.

One thing I was wondering was, if I misread the hydrometer and read 1.014 when it was actually showing 1.016, for a FG of 1.103 would this be enough to lead to the foaming I've described?

 

[felten]

I'd like to understand what's happened so could someone explain how infection leads to more carbonation.

Is a wild yeast able to ferment sugars that yeasts like S04 and US05 can't?

Yep, definitely.

some good information on causes here... further down the thread.

 

[Deebo]

If only half of the bottles are bulging and it tastes ok.. did you make sure the priming sugar was properly dissolved/distributed throughout the beer?

 

[cpsmusic]

If only half of the bottles are bulging and it tastes ok.. did you make sure the priming sugar was properly dissolved/distributed throughout the beer?

Yes, that's another thing I was considering. What I do is dissolve the dex in hot water, put it in a secondary vessel, and then rack the beer into the secondary. I usually give a gentle stir too. I guess this might mean that the priming sugar isn't evenly mixed. Next batch I'll make sure it's well mixed.

 

[cpsmusic]

I let some of the JSAA go flat overnight and took a gravity reading this afternoon. It's showing 1.006 - that seems too low.

 

[malt_shovel]

I let some of the JSAA go flat overnight and took a gravity reading this afternoon. It's showing 1.006 - that seems too low.

Yep,

Looking at the grain bill (approx 95% base malts, with 5% specialty) mashed at 68oC should leave a decent amount of body / non-fermentables, particularly with S-04 (not as attenuative as US-05). 1.012 - 1.014 would be about right me thinks. 1.006 indicates an infection to me.

As Ross says, if they are still drinking well, throw them in the coldest fridge space and enjoy them quickly. I would recommend against re-using the yeast from this ferment for any further batches.

Give the brewhouse a clean out with your favorite sanitizer before the next batch.

Cheers
:beer:

 

[cpsmusic]

Yep,

Looking at the grain bill (approx 95% base malts, with 5% specialty) mashed at 68oC should leave a decent amount of body / non-fermentables, particularly with S-04 (not as attenuative as US-05). 1.012 - 1.014 would be about right me thinks. 1.006 indicates an infection to me.

As Ross says, if they are still drinking well, throw them in the coldest fridge space and enjoy them quickly. I would recommend against re-using the yeast from this ferment for any further batches.

Give the brewhouse a clean out with your favorite sanitizer before the next batch.

Cheers
:beer:

I was having a think about this today. I'm pretty careful with my (primitive) brewery equipment, and because some of the bottles in each batch are OK, I think that the problem might lie with the cleanliness of my bottles. I've recently started reusing my PET bottles and I think that for the next batch I'll pay extra special attention to making sure the bottles are 100% clean. ATM, what I do is wash them with a mild detergent and then sanitize them with Brewshield however I'm thinking that in some cases this might not be enough to completely clean the bottle. I might try really hot water although I'm a bit unsure as to how the plastic will handle this.

Cheers,

Chris

 

[ShredMaster]

I was having a think about this today. I'm pretty careful with my (primitive) brewery equipment, and because some of the bottles in each batch are OK, I think that the problem might lie with the cleanliness of my bottles. I've recently started reusing my PET bottles and I think that for the next batch I'll pay extra special attention to making sure the bottles are 100% clean. ATM, what I do is wash them with a mild detergent and then sanitize them with Brewshield however I'm thinking that in some cases this might not be enough to completely clean the bottle. I might try really hot water although I'm a bit unsure as to how the plastic will handle this.

Cheers,

Chris

Good work mate! It would agree with Ross's earlier response, it could be an infection taking place.

If there was an issue with the batch such as (but not limited to) being over primed or bottled too early, the WHOLE batch would be affected. If it is selected bottles, it is more likely to be a type of infection from those specific bottles rather than a batch issue. From what you've said so far, you seem to have the hang of the numbers quite ok so write this couple of batches off as "improper sanitation" and make a concentrated effort to eliminate that in the next couple of batches and see how you go.

Good luck!

Cheers,
Shred.

 

[bum]

ATM, what I do is wash them with a mild detergent...however I'm thinking that in some cases this might not be enough to completely clean the bottle.

Yep, if you're talking something like dishwashing liquid you possibly need to kick it up a notch. Have a think about cleaning them in the same manner you clean your brewery gear and see if that takes care of it then scale back as (if) you see fit. Remember that sanitiser can't work correctly if the bottles aren't properly cleaned to begin with.