cider fermentation restarted after three weeks - paranoia

[amorphia]

Hi!

I have 30 litres of cider which seemes to have finished fermenting (was down from more than a bubble a minute at the start through the airlock to less than one every five minutes). I cracked open the bucket to test it a couple of days ago. Test test (very dry) and specific gravity measures confirmed that close to all the sugar was fermented. I siphoned off a couple of litres and closed the lid again, planned to rack if off into a demijohn for maturing, once I'd got hold of one.

A couple of days after that, it has started bubbling a lot again, more than once a week. Given that all the sugar was gone, I am really paranoid something got in and is turning the alcohol to vinegar. Is that likely? What I hope happened instead is that the sediment (which is thick) got stirred up and more sugar was put into solution. How do I know which happened and what can I do?

Cheers,

Ben

 

[Bowtiebrewery]

well how confident are you in your sanitation of your testing equipment? That is where i would base your suspicions off of.

If you believe that you did everything right, you are probably fine.

 

[amorphia]

Thanks for the answer! I am pretty confident - I used ample amounts of the right sort of disinfectant on the siphon and the gravity tester.

But once you expose to the atmosphere, you can never be sure that some wild vinegar making yeast might not get in, isn't that right?

Is what I am observing consistent with an infection with wild vinegar making yeast?

I have some stuff called "yeast stop" (translated from Swedish). I'm not sure exactly what's in it, it's a packet without further description I bought from the brewing shop. Should I add it at this point perhaps?

Is there also bacteria which can turn ethanol to vinegar?

Other random stuff which might be useful information: I am using juice I pressed myself from apples so there is definitly a lot of apple bits in the sediment at the bottom. I used ale yeast at the beginning, a few days after adding sulfites to inhibit wild yeast.

Any more opinions much appreciated!

Cheers,

Ben

 

[Revvy]

Your fermentation didn't start, your airlock started bubbling because you opened it up to take a reading and closed it back up. And now it is off gassing the co2 that had built up and then sat undisturbed since you pitched your yeast, or racked it, or did whatever else you did awhile ago.

Guys, airlock bubbling and fermentation are not the same thing. You have to separate that from your mindset. Airlock bubbling can be a sign of fermentation, but not a good one, because the airlock will often blip or not blip for various other reasons...so it is a tenuous connection at best.

If your airlock was bubbling and stopped---It doesn't mean fermentation has stopped.

If you airlock isn't bubbling, it doesn't mean your fermentation hasn't started....

If your airlock starts bubbling, it really doesn't matter.

If your airlock NEVER bubbles, it doesn't mean anything is wrong or right.

Your airlock is not a fermentation gauge, it is a VALVE to release excess co2. If it bubbles it is because it needs to, if it doesn't, it just means it doesn't need too...

Often an airlock will bubble if the fermenter has been disturbed in some way, like a change in temperature, change in atmospheric pressure, the cat brushing against it, or opening it up to take a hydro reading.

The co2 has sat in stasis for a period of time, then it was disturbed so it is not longer at equilibrium with everything else now. And therefore it is blipping in your airlock...nothing else.

 

[amorphia]

I've been doing some more reading. Please correct me if I'm wrong, but:

It can't be something producing vinegar, because what does that is acetobacter, and that using oxygen and produces no gas. So it would not be causing a pressure increase in the bucket.

It _could_ be lactobacillus because that ferments sugar into vinegar, and in the case of heterlactic fermentation that produces CO2.

Or it could just be that the desired fermentation has kicked off again. But how likely is that?

Cheers,

Ben

 

[Revvy]

I've been doing some more reading. Please correct me if I'm wrong, but:

It can't be something producing vinegar, because what does that is acetobacter, and that using oxygen and produces no gas. So it would not be causing a pressure increase in the bucket.

It _could_ be lactobacillus because that ferments sugar into vinegar, and in the case of heterlactic fermentation that produces CO2.

Or it could just be that the desired fermentation has kicked off again. But how likely is that?

Cheers,

Ben

Or even more likely like I said above, you disturbed the integrity of the co2 in the fermenter when you opened it up to take your hydro reading, and put the stopper back on.

Usually the simplest reason is the right one.

 

[amorphia]

Thanks very much for your reply Revvy! (which I only read after posting my last post).

I have a kind of bucket with a really really tight lid so I'm confident that gas doesn't escape. But the explanation about how disturbing the brew can make it release gas really fits what I am observing. So now I am hoping that's what going on.

Cheers!

Ben

 

[Revvy]

Thanks very much for your reply Revvy! (which I only read after posting my last post).

I have a kind of bucket with a really really tight lid so I'm confident that gas doesn't escape. But the explanation about how disturbing the brew can make it release gas really fits what I am observing. So now I am hoping that's what going on.

Cheers!

Ben

It is, believe me....you are being way paranoid over something that happens all the time. Don't always assume something wrong, 99.95% of the time when you think something is wrong, it isn't.

You've even MORE confirmed that it is offgassed co2, since you uncracked a TIGHT lid on your bucket, and then snapped it back on, that you disturbed the sediment layer on the bottom, where a ton of co2 is trapped and you knocked it out of solution and it is coming to the surface. You probably gave it a really good nudge when you put the lid back on.

Think about this, when you lowered the lid back onto the bucket, you were pushing AIR ahead of it, right into the bucket, so now you have air and co2 in a space where there was JUST a fixed amount of co2...SO now what was in stasis, is now co2 + a volume of air...so now the co2 is going to push the o2 back out...where???? The airlock of course...Blip Blip Blip anyone?????

Again, if you separate the idea of airlock bubbling from fermentation, you worry less about crap like this.

 

[Yooper]

One thing I would suggest is to get that cider in a proper carboy or demijohn as soon as you can. By siphoning some out, and leaving it in a bucket, you've left a ton of headspace. Oxidation can ruin cider, so I'd siphon it to a vessel with very little headspace right away. You also benefit the cider by getting it off of the lees (all that sediment).

 

[amorphia]

Thanks a lot for talking me down from my panic folks!

I'm a first time brewer as you can probably tell!

I never would have got into brewing if it hadn't sickened me to see so many apples rotting on the ground in my part of Stockholm last Autumn... but I can see it becoming a habit now...

I brought a 25 litre demijohn today so the cider will be getting off the lees and loosing its headspace tomorrow.

Cheers!

Ben

 

[daugenet]

If you really want to know for sure if it has started back up (which is unlikely) then you need to take another reading.

 

[Revvy]

If you really want to know for sure if it has started back up (which is unlikely) then you need to take another reading.

But then he'll make it bubble again....or maybe it will stop.

It's really not worth it, and he doesn't really need to possibly ACTUALLY infected it by fiddling too much with it.