Scum in Carboy

[QuiQuog]

The picture below is Chilean Zinfandel that I started in early May of this year. There’s a scum forming in the neck of the carboy. At first it looked like a greasy film on top of the wine. I thought it was the byproduct of the Wyeast MLF packet I added so I didn’t pay much attention to it. Now it’s climbing up the sides of the neck. If I shake the carboy to splash it up the side of the neck, it washes the scum off as in the second picture.
Any ideas what this is, or how to treat it?

 

[Jim Welch]

Have you taken any out? Kind of hard to tell but it looks like it has a granular texture if I zoom in on my phone here. If it feels like sand and “melts” from body heat it is probably tartaric acid. I had some floating on one of my wines once and with the help of folks here was able to figure it out. Mine didn’t have the “scum” component and didn’t climb though, it just floated.

 

[Ohio Bob]

Did you add the MLF packet to this carboy? Has the appearance I’d expect if you did.

 

[QuiQuog]

Have you taken any out? Kind of hard to tell but it looks like it has a granular texture if I zoom in on my phone here. If it feels like sand and “melts” from body heat it is probably tartaric acid. I had some floating on one of my wines once and with the help of folks here was able to figure it out. Mine didn’t have the “scum” component and didn’t climb though, it just floated.

I sampled it a couple of times and re-topped with wine, although I didn’t touch the stuff. I plunged the baster below the surface so as not to get whatever is is in my sample. Doesn’t seem to affect the wine in any noticeable way right now. I just felt it. It’s not sandy, just wet.

 

[QuiQuog]

Did you add the MLF packet to this carboy? Has the appearance I’d expect if you did.

I added the Packet on day 2 of fermentation with 3 week extended maceration. Is this typical of MLF? Does it indicate anything?

 

[QuiQuog]

Just bumping this to try and get some more input.

 

[QuiQuog]

So here it is a month later without touching it. The scum climbed up the sides again. It’s also on the surface, and the oak cubes I added never sank, as you can see in the second picture. They were added about 4 months ago. What should I do about this?

 

[VinesnBines]

I would assume it is mycoderma or flowers of wine. Soak a paper towel in a solution of kmeta (2 ozs in a gallon of water) . Use the towel to soak up the first 1/4 inceh or so of wine. Take another kmeta paper towel and wipe the inside neck of the carboy. Add a good dose of kmeta at least 1/4 tsp for 6 gallons and maybe a little more. Top up with wine to within 1/2 inch of the stopper. Sanitize a clean stopper and airlock. If you have some Everclear you can put a few drops or more as the final top up. Keep a watch on the wine and repeat if it returns.

If you want to another carboy, I would suggest removing the scum with the kmeta paper towel and cleaning the neck of the carboy before attempting to rack.

I have an ongoing battle with surface mycoderma. I use this method and have never had an infection so severe it ruined the wine. If you leave it though it will continue to grow and will ruin the wine.

 

[QuiQuog]

I would assume it is mycoderma or flowers of wine. Soak a paper towel in a solution of kmeta (2 ozs in a gallon of water) . Use the towel to soak up the first 1/4 inceh or so of wine. Take another kmeta paper towel and wipe the inside neck of the carboy. Add a good dose of kmeta at least 1/4 tsp for 6 gallons and maybe a little more. Top up with wine to within 1/2 inch of the stopper. Sanitize a clean stopper and airlock. If you have some Everclear you can put a few drops or more as the final top up. Keep a watch on the wine and repeat if it returns.

If you want to another carboy, I would suggest removing the scum with the kmeta paper towel and cleaning the neck of the carboy before attempting to rack.

I have an ongoing battle with surface mycoderma. I use this method and have never had an infection so severe it ruined the wine. If you leave it though it will continue to grow and will ruin the wine.

That sounds reasonable. I’ll do it this afternoon. Thank you

 

[VinesnBines]

It may not be mycoderma but why risk it? This procedure won’t hurt a thing. Good luck.

 

[BigDaveK]

Great advice by VinesnBines.
FWIW, I've read mycoderma is aerobic.
Whenever I open a jug or carboy and replace the airlock I give it a shake, hoping to degass a little to fill that void.
Yes, good luck.