White stuff over fermenting cider

[BrasseurduRuisseau]

Hello everyone,

This is my second time home brewing cider and I haven't seen this before. I had 50l of cider fermenting in a keg, which I then transferred into two 25l carboys. One of them seems to be doing fine, but the other has this weird white stuff covering the top. It's not moss, but I can't tell what it is exactly. Any clues?

 

[dwhite60]

Looks like fermentation bubbles.

I say you're good. Cider doesn't get the krausen beer does.

 

[Rick Stephens]

It looks like a pellicle to me. Kind of dry and powdery. Comes from too much headspace and surface area that allows oxygen into the must. If you touch it it will fall into the must and is hard to get entirely out. Short term is not a hazard, not sure what long term storage implication are of having it present.

My fix is once racked to secondary to always fill the carboy up until I have minimum headspace at the top. I just use a good store bought cider or juice for this. Here's two carboys in primary and the one on the left in secondary. You can see how little surface area and air is captured to minimize oxygen contamination.

 

[BrasseurduRuisseau]

Thanks for the replies!

So Rick, if I understood clearly, would you suggest I get some additional (e.g. a store-brought can) to add into my carboy to take up more space? And I assume, before that, trying to remove as much white stuff as possible.

This explanation seems plausible though, since my other carboy which doesn't have that problem has cider taking up more space.

I have uploaded better pictures below to give a better image:

 

[Epond83]

Would purging the head space with CO2 help? If you had a tank of CO2 available of course.

 

[Rick Stephens]

Surface area, surface area, surface area. Rack it off and get rid of the dry pellicle and then fill near to the top. From now on, do that when you rack the first time and you won't see a pellicle form at all.

Yes, you can purge with C02, but in this case the process has already started. A pellicle is an oxygen and bacterial process. Not terribly bad compared to many other things that could happen, but the possibility is always there to add funky taste when you have a pelllicle growing.

 

[BrasseurduRuisseau]

Ok I just have one more question. If I open the carboy to remove the pellicles, won't that introduce more oxygen in it? How do I minimize this risk?

 

[Rick Stephens]

Rack it into a bucket and leave the pellicle behind. Even if you leave behind a cup of cider to accomplish it. Wash your carboy, rack back into it and top it off. Picture below has one bottle in secondary on the left, topped off for the long haul, and two in primary.

 

[BrasseurduRuisseau]

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