Apple ginger raisin metheglin and mycoderma

[Silenoz]

Hej,

I am in the process of making the above mentioned metheglin and suspect I might have mycoderma. Because of all the needed stirring and ingredients in bags I started the 12 L batch of metheglin in a 25 L bucket. All went well and it tasted like it might become the best metheglin so far, but after the primary fermentation was over I might have left it in the bucket for a bit too long. I stopped stirring with the winewisp after day 8 and left it for about 7 more days after that ( I can check my notes there). When I was going to rack the metheglin to a demijohn I noticed a slight whitish film divided in small patches on top, but didn't (want to) think too much of it. But now I don't know, could it be mycoderma.
The wine was well over 14 % in alcohol already before day 8 and didn't show anything strange at that point. Is there a alcohol tollerance limit for mycoderma, I have read in a variety of places that when wine is over 12% it is protected from spoilage by micro organisms, or should that read most spoilage? Does this include mycoderma? Or is mycoderma to big of a variety of potential bactieria or yeasts that it is impossible to say/guerantee that mycoderma does not occur over a certain ABV?

 

[salcoco]

mycoderma or "flowers of wine" is not abv oriented but a result of oxygen exposure. the 7 days in the bucket after fermentation without a airlock or k-meta is the culprit. just rack from bottom up as the bacteria feeds from the top down eating alcohol and leaving water behind. do a double dosage of K-meta and get it under airlock now. keep an eye on it because it can reoccur. if so do the same again and bottle consume quickly.

 

[Silenoz]

Thanks for the advice!
I did airlook it, but the bucket was really big compared to the volume of the metheglyn (2,5 times the volume), I expect that that is where the excess oxygen came in, after openening it one time too many after the yeasting process subdued.

I managed to solve it though, by by using your advice combined with flooding and fortifying afterwards.

A great metheglyn got saved! Thank you!