Sorry, it's another 'Is my beer contaminated thread!'

[khumbu76]

Hi everybody. I just ran into a pretty unique situation while kegging some hard cider today and after digging through the forum and some google searches, couldn't quite find an answer to this one.

I noticed 2 small floating mold-like objects floating at the top of my hard cider. Each were about the size of a quarter. I thought, 'oh crap, pellicles!' But they seemed to have more of an elastic feel to them almost like a couple of mini, kombucha scobys. And they didn't seem to look like a yeast raft. They were not there before I transferred to a secondary. So they must have popped up over the last 3 weeks in the secondary.

I am very thorough when it comes to sanitizing my equipment. I've never had an infection (knock on wood). So, I think these little buggers could be 1 of 3 things:

1 - Pellicles brought on by a combo of too much head space (5 gallon batch in an 8-gallon fermentor) and the fact that I disturbed the Co2 layer when adding in chopped ginger for the final week.

2 - Something possibly came in on the ginger. I soaked both the ginger chunks and muslin bag in starsan before adding. And from what I hear, ginger is naturally anti-microbial. Combined with the fact that the batch is also at 5.9%, I should have been good. But, maybe I should have boiled them for a few minutes instead?

3- Here's the wildcard. I also brew kombucha. Would it be possible that there is some sort of scoby residue that grew a couple of mini-scoby's? I used this fermenter for kombucha brewing but cleaned with an overnight soak in PBW and sanitized with starsan per usual. The fermenter was empty and dry for about 5 months, but I know bacteria can be pretty hardy.

I would like to know what your thoughts on what these little things are. And do you guys think I should take a nuclear approach to cleaning everything that may have come in contact with this batch? From what I hear, pellicle contamination can contaminate batch to batch if not killed with bleach.

Bonus question: Do you think it's ok to use the same fermentation equipment for Kombucha as cider and beer? Or should I treat scoby residue as if it's a highly infectious, outbreak-like contaminant?

Photo attached of mystery contaminant in fermentor (tannish/white disks)

Thank you all for any info! I've learned a ton from this forum over the years, so thank you everyone for maintaining this awesome community!

 

[RPh_Guy]

Sanitation goes out the window when you add unpasteurized ingredients. Ginger is covered with wild microbes. Therefore your cider was not sanitary whatsoever.

If you want a clean cider, when you secondary you need to reduce headspace and use sulfite to control wild microbes.

A kombucha SCOBY forms a pellicle (i.e. the snot pancake is a pellicle). There's no such thing as a mini-SCOBY.

Your photo is very unclear, but it looks more like mold than anything. Were the floaties fuzzy or hairy, looking at them up close?
Mold is potentially dangerous, since it is allergenic and can produce toxins and carcinogens. Cider with mold should be dumped, so it's important to identify whether it's mold.
Wild yeast and bacteria will usually not form little discs, but rather a film across the entire surface.

For cleaning I recommend a warm PBW soak and an acid rinse, with warm water rinses before and after each step. Break down all valves and such for cleaning. This process is all you need. If items are in storage for a while, give them another rinse before sanitizing. Sanitize things before and after assembling, immediately before use.
Bleach is unnecessary and probably not even helpful.

If you want to use the same equipment for wild microbes (e.g. kombucha) and clean batches, you need to use a very thorough cleaning regimen, as described above. Make sure nothing abrasive is used on plastic because micro-abrasions can harbor wild microbes.
Many people do keep separate equipment just to be more safe.

 

[Vale71]

1 - Pellicles brought on by a combo of too much head space (5 gallon batch in an 8-gallon fermentor) and the fact that I disturbed the Co2 layer when adding in chopped ginger for the final week.

The CO2 layer simply does not exist so no need to worry about disturbing something that is not there in the first place. You certainly had plenty of oxygen in the fermenter and that would create very favorable conditions for catching something aerobic such as mold or acetobacter.

2 - Something possibly came in on the ginger. I soaked both the ginger chunks and muslin bag in starsan before adding. And from what I hear, ginger is naturally anti-microbial. Combined with the fact that the batch is also at 5.9%, I should have been good. But, maybe I should have boiled them for a few minutes instead?

You can rest assured that there was plenty of microbial fauna on those chunks. The only effective treatment against that would be heat treatment.

3- Here's the wildcard. I also brew kombucha. Would it be possible that there is some sort of scoby residue that grew a couple of mini-scoby's? I used this fermenter for kombucha brewing but cleaned with an overnight soak in PBW and sanitized with starsan per usual. The fermenter was empty and dry for about 5 months, but I know bacteria can be pretty hardy.

This is certainly a possibility. You had aerobic conditions and you also had fresh yeast from the cider fermentation, it's possible that it might have formed a new SCOBY that had just started to become visible when you decided to transfer.

 

[khumbu76]

Thanks so much for the info @Vale71 and @RPh_Guy . It did appear that there was a fine, white fuzz covering the disks. I did look like mold. But what really confused me was the texture of the disks. They were about 1 mm thick, tan and almost elastic in feel. They actually stretched just a bit before tearing, I wish I took a photo of one in my hand for reference.

If they came in with the ginger, they would have grown in the past 7 days. However, if it was infection from kombucha, it would have had about a month to grow in the secondary. Unfortunately, I did not look down on the batch before adding the ginger.

My operating procedure for cleaning/sanitizing equipment has always been very thorough. So, it sounds like it was most likely the ginger. In the future, I will treat with heat!

But, I will certainly dedicate one fermenter to kombucha-only brewing and reserve the others for beer/cider just in case there happens to be something lingering in an unseen micro-scratch in the Speidel fermenter. That’s a good call.

Sounds like I should just dump the keg to be safe, eh?

Thanks again for the info.

 

[RPh_Guy]

It did appear that there was a fine, white fuzz covering the disks. I did look like mold. But what really confused me was the texture of the disks. They were about 1 mm thick, tan and almost elastic in feel. They actually stretched just a bit before tearing, I wish I took a photo of one in my hand for reference.

Definitely mold.
It not unusual for mold to form thick pads. In fact, that's how it usually grows on top of a liquid.

There were probably lots of mold spores from the ginger, but mold spores float around in the air, so they could have entered at any point. You can't easily avoid mold spores.
Mold requires oxygen to grow. That's why oxygen avoidance and sulfite are important.

Sounds like I should just dump the keg to be safe, eh?

Yes, for sure. Sorry about that.

 

[khumbu76]

Definitely mold.
It not unusual for mold to form thick pads. In fact, that's how it usually grows on top of a liquid.

There were probably lots of mold spores from the ginger, but mold spores float around in the air, so they could have entered at any point. You can't easily avoid mold spores.
Mold requires oxygen to grow. That's why oxygen avoidance and sulfite are important.

Yes, for sure. Sorry about that.

Right on -- thanks again for the info. The good news is that I had a second (dry-hopped) batch going at the same time. So, the kegerator won't be completely empty!