Fermentation started back up!

[EFBacon]

I know that this is not an unusual circumstance in and of itself but..something very interesting just happened.

I have a 1 gallon batch of lemon/lime/ginger mead that I started on 5/11/13. It is more or less a JAOM variant. Here is my recipe:

Zest of 3 limes/3 lemons
3.5 lbs orange blossom honey
1 whole ginger root, shredded
1 stick of cinnamon

On 8/18/13, I racked it to a new container as most of the fruit was sinking or done sinking. It was very clear, and the ABV came out at approx. 9.19%.

I know already that changing the JAOM recipe "voids the warranty"; I love changing it and experimenting and have had some great results! I suppose I should get to the point already..

I went into the cabinet where the mead has been sitting quietly, to grab the dry food to feed our cats, and noticed that there were thing floating in the mead. I was at first worried that it was some kind of contaminant, but I'm pretty good about keeping it safe. When I pulled it out I realized it was some leftover citrus pulp that must have been in the sediment on the bottom, and realized it was fizzing a bit. I opened the cap and it made a sound like what you'd hear opening a soda lol--at which point it really started going. It appears to have started up again! Here we are and it's almost October, and I was thinking about bottling it soon. I'm glad I checked on it tonight--I quickly installed the air lock once again and it's just fizzing away.

I'm curious as to what might have started what appears to be the fermentation process all over again? I have not added anything to it or otherwise disturbed it beyond when I racked it and used my hydrometer to measure it. In any case, it's exciting heh--and it tastes great. I have read about fermentation starting up again but this is a first for me personally, and of course any feedback/thoughts would be much appreciated! I'm not concerned as much as I am excited, interestingly enough lol. I do wonder if it's something typical of this type of mead or if it's something I did, or if it's just sheer chance and the yeast inside had somehow gone dormant or something and are now active again.

Thanks in advance for your time--sorry for the novel, I am a lengthy typer/talker.

 

[Medsen Fey]

It is hard to say exactly what triggers yeast to restart, but there are some things that are likely. One of the most common is warming up. This is particularly true for cool fermentations that didn't get to finish out at a higher temperature. Did your storage area get warmer recently?

Undernourished yeast also are prone to this. As some of their brethren die off and release amino acids into the mead, the yeast cells that are viable can start up again. This autolysis can also release potassium and substances that shift the pH up slightly. This may be enough to allow some dormant cells to reactivate.

There may be many factors that can impact refermentation, but the key things are that they are unpredictable, and they have been documented to occur even as much as 3 years after fermentation "finished". If you have a mead with residual sugar, and the yeast have not reached their ABV tolerance, not stabilizing such meads is an open invitation for bottle bombs that can be positively dangerous.




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[EFBacon]

Thanks for the insight Medsen! Now that you mention it, the cabinet it's in is directly next to the oven, perhaps over time the warmth from the oven could have contributed. Not that it's on all the time lol.

Would a refermentation theoretically boost the ABV a bit, and would it do much to the flavor?

And yea bottle bombs--trying to avoid those at all costs lol. Scary thought.

Thanks again!

 

[Medsen Fey]

It will increase the ABV. Effect on flavor is variable, but I've not had it ever ruin a batch.



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[Chevette Girl]

Things can also clear and drop while still be fermenting just a little bit, I've had several batches like that, which is why I would never, ever cap or bottle something that's not been stabilized unless it's been under airlock for a year or two (except JAO's, but I always have a screw-top bottle when I bottle a JAO batch so I can periodically loosen the cap and listen for signs of carbonation, I've only had two of forty JAO variations restart after bottling).

 

[Fisk Jaegaren]

If you are happy with the flavor and ABV why not cold crash, stabilize with sorbate and a campden tablet and bottle?

 

[Medsen Fey]

If you are happy with the flavor and ABV why not cold crash, stabilize with sorbate and a campden tablet and bottle?

This approach works fine, but it helps if you make sure that the sorbate and sulfite have have actually stabilized the mead, and that means watching it for a few weeks to insure stability of the gravity. You may also want to give it time to clear (or to fine it) before you bottle.

In this case, with 71B, if you started at 1.130, the yeast are pretty much at their tolerance at 1.020 so they will likely remain stable.

 

[Fisk Jaegaren]

This approach works fine, but it helps if you make sure that the sorbate and sulfite have have actually stabilized the mead, and that means watching it for a few weeks to insure stability of the gravity. You may also want to give it time to clear (or to fine it) before you bottle.

In this case, with 71B, if you started at 1.130, the yeast are pretty much at their tolerance at 1.020 so they will likely remain stable.

Yes, time is needed in those steps, didn't mean for it to be taken as something you would do in one night!