Weird white skin on cider

[dannythemanny]

Evening all,

I have researched this a bit on other threads and in other forums and I'm not sure what new information I'm expecting to find here, but here goes...

I collected about 70kg of apples back in August/September and had then pressed into juice. The juice started fermenting on its own immediately, even before I had time to get it in the fermenter. I put about 20L in a pail and another 5L in a small demijohn.

To the 20L batch, I added several teaspoons of Young's yeast along with some sugar to bump up ABV a couple of points. It fermented like nobody's business and I racked to secondary after about ten days, I think. The 5L batch received no other yeast or sugar - just wanted to experiment and see what happened, and I never racked that one. I'm fairly sure I added no campden to either fermenter.

I moved them out to the garden shed and went to France for 10 weeks. On returning, I was surprised to see a white skin had formed across the larger fermenter (Young's yeast) and little spots of what I thought looked like mold had formed on the surface of the wild fermented one.
 
In doing a bit of digging online, I'm somewhat encouraged to see people saying that mold on cider is very obviously mold - usually blue, green or black and fuzzy. These almost look more like calcium deposits or something. I think they may be what's referred to as 'film yeast', but I'm predominately a beer brewer and sanitise *everything* religiously, so haven't come across this before. I just thought I could be a little more laissez-faire with cider for some reason.

I've attached pictures. Very curious to know what people reckon it is and whether it is potentially harmful. My other half is a scientist, so I have access to microscopes but wouldn't have a clue what to look for!

Cheers.

 

[geigercntr]

Looks like a pellicle to me! If so, it's not going to be mold, but some combo of yeast and bacteria.

 

[dannythemanny]

Looks like a pellicle to me! If so, it's not going to be mold, but some combo of yeast and bacteria.

Thanks. I think I'm going to give it a taste and all being well, rack it into a corny keg for treatment with campden and back sweetening, then bottle it up... All being well, that is. If I do manage to get it under a microscope, I'll stick the pics up here if I can!

 

[dannythemanny]

Couldn't get a very good zoom on the microscope, unfortunately, so perhaps inconclusive...

 

[dannythemanny]

Tastes fantastic. Probably the best I've made, I reckon (this being my third cider). I racked to another vessel onto 7 crushed campden tablets and purged with co2. Will backsweeten and bottle in the next few days.

The skin was left down the side of the carboy (see pics).

The one that fermented under its own steam I think I may dump as I noticed weird sort of tendril things growing down from the clumps on the surface (see pics).

 

[geigercntr]

Brill. I'm yet to make a cider myself, but have pals who do them regularly. Their 'wild' fermentations with no added yeasts have always come out the best. Excellent stuff. Enjoy!