Obligatory newbie mold panic thread

[arthur_the_doc]

Dear Brewers,

As a novice beer and wine brewer, I've been covertly absorbing tips from this forum on and off for a few months now, and am today motivated to post myself by the ultimate horror: a brew infection!

I left my white wine in secondary a few weeks longer than advised in my kit, and discovered white cobwebs growing in the neck of my carboy. I decided this meant it was time to rack to my bottling bucket, but in the process of moving it off the floor, the cobwebs (I am assuming mould) was knocked into the wine.

No matter, I thought to myself, I will leave it alone for a few hours and rack once it has settled to the top / bottom. No such luck: the bulk of the mould particles have suspended themselves in a layer in the very middle of my carboy, with the exception of a few clumps going for joyrides up and down again.

I read in another thread that cooling beer to 45° caused mould to fall out in another brewer's case, so I have put my carboy outside for the night (we have a low of 35° forecast for tonight) with a plastic bag over the top (in case of rain) so that I can rack it first thing in the morning.

Does that make sense? Any other suggestions? It seems appropriate to take a separation step like this to avoid installing a tiny bit of mould in every single wine bottle!

 

[Yooper]

Dear Brewers,

As a novice beer and wine brewer, I've been covertly absorbing tips from this forum on and off for a few months now, and am today motivated to post myself by the ultimate horror: a brew infection!

I left my white wine in secondary a few weeks longer than advised in my kit, and discovered white cobwebs growing in the neck of my carboy. I decided this meant it was time to rack to my bottling bucket, but in the process of moving it off the floor, the cobwebs (I am assuming mould) was knocked into the wine.

No matter, I thought to myself, I will leave it alone for a few hours and rack once it has settled to the top / bottom. No such luck: the bulk of the mould particles have suspended themselves in a layer in the very middle of my carboy, with the exception of a few clumps going for joyrides up and down again.

I read in another thread that cooling beer to 45° caused mould to fall out in another brewer's case, so I have put my carboy outside for the night (we have a low of 35° forecast for tonight) with a plastic bag over the top (in case of rain) so that I can rack it first thing in the morning.

Does that make sense? Any other suggestions? It seems appropriate to take a separation step like this to avoid installing a tiny bit of mould in every single wine bottle!

You must have had some headspace in the carboy- mold can't form if you top up to the top near the bung. You'll know for next time.

For this time, you can crush one campden tablet per gallon in some (1/4 cup) boiling water, pour that into a carboy and rack the wine into it. Top up, allowing almost no headspace at all. Wait for a week to see if the mold reforms.

If the mold is on the top, try to rack under it, and not suck any of it up.

Let us know in a week or so if it's back!

 

[arthur_the_doc]

Thanks for the quick response. I had topped the carboy up to the level suggested in the kit instructions - right where the sloping sides converge and there is only a constant 1-2" of constant neck diameter to the top. However, I used a sanitized-during-a-previous-batch-and-left-in-the-cupboard bung without sanitizing it again. That probably caused the trouble!

I should have mentioned that about 3 weeks before the mould appeared I had added the metabisulphite, kieselsol and chitosan that came with the kit.

I haven't used campden tablets before. Wikipedia says they're for bacteria infections, though. Will they also kill mould? Also, I don't have any: should I rack now and meanwhile rush order them from an online brew store, or wait until I have them in hand before racking?

 

[arthur_the_doc]

Also, I should point out the mould doesn't look like most mould pics I have seen on the forum: rather than scum on the surface, it was white cobwebs in the tiny neck space that were also touching the surface. It's possible that's just because there wasn't much surface for them to hang out on (about 1-2" diameter neck).

 

[Yooper]

You don't have a homebrew store close, or a friend who makes wine? It's too bad you'd have to ship such a small item.

Campden tablets (potassium metabisulfite) are commonly used in winemaking, so if you're planning another batch, or bottling this one, you'll want them anyway but you can wait until you get them if you have to.

 

[arthur_the_doc]

Aha - is potassium metabisulphite likely the same as the generic metabisulphite that I added from the kit? In that case it should be in the wine already, exerting its killing power. That might be why the mould wasn't doing a very good job of colonizing the brew, just touching the surface. Or does metabisulphite use up its killing power within a certain period of being added? Should I add more anyway?

Yes, I'm afraid the closest homebrew store is a long drive off, and I don't own a car. For the record, it's not easy living in NJ without a car.

 

[Yooper]

Aha - is potassium metabisulphite likely the same as the generic metabisulphite that I added from the kit? In that case it should be in the wine already, exerting its killing power. That might be why the mould wasn't doing a very good job of colonizing the brew, just touching the surface. Or does metabisulphite use up its killing power within a certain period of being added? Should I add more anyway?

Yes, I'm afraid the closest homebrew store is a long drive off, and I don't own a car. For the record, it's not easy living in NJ without a car.

Yes, but they only give you a tiny bit as an antioxidant. I'm thinking that you didn't top up(following instructions) but left it in secondary longer than instructed (which is ok if you top up!), allowing some mold to take hold. You definitely need to add more sulfites if you want to halt this infection.

 

[arthur_the_doc]

Well, it took the entire week for the potassium metabisulphite to arrive, during which time I tried my hardest not to think about my brew!

As it turns out, the mould was not partial to living *in* the brew at all. It continued to float listlessly - yet stubbornly - in suspension 50% of the way up my carboy for the entire week, which would have made racking around it difficult. I'm guessing that since it started off in the neck, it was not bioengineered to live in suspension or to deal with the bio-weaponry of my yeast.

Things I learned:

1) leaving the carboy outside for the night chilled it enough (down to 50) that the mould fell out of suspension. After taking it inside again, the mould bits floated back up to exactly where it had been previously. Must be a density thing.
2) filtering your wine with a sub-micron filter is a great way to prevent any possibility of live mould (or spores) from making their way into your bottles, and has cosmetic and possibly taste benefits, too. I ended up ordering a hand filter with my metabisulphite, since I had been considering one anyway.
3) to be on the safe side, I added the metabisulphite to my bottling bucket after filtering, gave it a good stir, then bottled up. It tasted good!

Filtering and then adding metabisulphite was likely overkill, particularly since the submerged mould showed no signs of life, but it can't hurt either.

Thanks Yooper for talking me through this first (non) infection!

 

[WIP]

If you added the sulfites and it tasted good, you did a good thing. It will last longer in the bottle and be less prone to infection.