Mold on my fermenter (some pics)

So I was busy crash cooling, getting ready to gelatin when I took the shirt off my bucket and saw mold all over the lid.

I decided rather not to put gelatin in and cleaned the lid. I did this by pouring basically pure ClO2 on the lid, leaving it for a while, wiping off with a damp cloth.

Then I poured boiling water on the lid and left it for a bit.

Then some more ClO2 and cleaned it off.

Anyway, today comes and I double check and see that there's mold on the side of the bucket (here's where i was on the ball enough to take photos)







I've sprayed the bucket with a pretty strong solution of ClO2. It was around 100ppm and normal sanitizing requires around 4ppm. I'm going to rub it off later with a cloth.

So my question: How can I prevent mold like this from happening again? Primary sits like that for around 3 weeks usually, sometimes longer.

P.S. I'm not worried that it got into the beer, but it is annoying and I dont want to chance it.

Also, it was a brand new fermenter bucket. That's the first batch it's ever had

Keep the beer in a less damp environment, maybe a dehumidifier?

Surely that defeats the point of the swamp cooler thing?

The the swamp cooler alone isn't what is making your bucket moldy, if you're in a damp room that's what is doing it.

Throw some bleach in the swamp cooler water

I think your screenname says it all

bleach is a good idea.

Regarding starsan for mold: I don't know how well starsan would work here as mold is a fungus (so is yeast!). While bacteria are killed by starsan's low pH, fungi might not be affected. I'm not sure, so I'd go with the bleach idea.

wyzazz said:

Keep the beer in a less damp environment, maybe a dehumidifier?

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I love this forum, but some of the replies you get- you'd think some people were being paid by volume and rate of (irrelevant) one-line replies.

Clearly you are trying to achieve cooler fermentation temperatures by soaking your bucket in water. I note the blue ice units in the water.

A couple of potential solutions: (I acknowledge the bleach recommendations, but I am wary [call me a sissy] of bleach unnecessarily near my beer).

-First, instead of draping the wet shirt (if that is what the green t-shirt is doing there) over the bucket, you may be able to achieve the same overall coollness without it. The mold will have a harder time growing without a wet T-shirt to hide under (and the stagnant air under the T-shirt, to boot).

-I would try thoroughly cleaning the outside of the bucket, and then maybe spraying StarSan over it on a daily basis. I do not think that StarSan could kill a built-up, fuzzy patch of mold, but once the bulk of mold is gone, I think that single spores would have a hard time growing in a StarSan environment. (Yeast [fungi] only can grow in StarSan once it is diluted in wort to a degree that it is no longer deadly to yeast). I would try this solution, because I look at my fermenters every day, and this would give me an extra excuse to do so...

-With the StarSan solution above, you could also orient a box fan at the top part of the bucket. This would evaporate the StarSan solution that you spray on daily (concentrating the acid a bit), but would also dry the bucket (evaporation=cooling a bit) and deny stagnant air for the mold to grow in. You might get a tiny bit more surface evaporation in your "cooler bath" bucket, maybe cooling the entire thing a tiny degree. (With this, if the air in your fermentation room is already saturated, then cracking a window if available/possible may help [if the outdoor air is also not already 100% humidity]).

...I'm no expert or mold biologist... Dang mold- so persistent and prevalent!

Hey! You could just make a 30 gallon starter, or just collect a yeast cake- and put it in a spray bottle... Inoculate the entire room with brewer's yeast so that all of the other microorganisms are crowded out! Man, I might just go into that lucrative, voodoo anti-mold business after all!

Try not using the t-shirt, and I like to put just a touch of bleach in the swamp cooler water. Also, FWIW after the first week when fermentation is complete, temps are not as critical and you could do without the swamp cooler perhaps.

With regards to the post above, how the hell would a swamp cooler work in a drier environment? HAH

wyzazz said:

Keep the beer in a less damp environment, maybe a dehumidifier?

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The primary is sitting in a tub of water! How on earth can you keep it drier?

I would suggest some bleach in the tub itself would keep mold growth down. Also changing the shirt or cover used over the primary every day or 2 to reduce potential for growth. A fan to move air will also aid in reducing the growth. Mold likes stale moist air I believe.

Salute!

Rub some tea tree oil on the bucket. Add some white vinegar to the water in the tub (not as nasty as bleach).

2 short sentences, how much did I earn?

bmckee56 said:

The primary is sitting in a tub of water! How on earth can you keep it drier?

I would suggest some bleach in the tub itself would keep mold growth down. Also changing the shirt or cover used over the primary every day or 2 to reduce potential for growth. A fan to move air will also aid in reducing the growth. Mold likes stale moist air I believe.

Salute!

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Keeping the ambient air drier (dehumidifier) should keep the mold down. I realize it's sitting in a tub of water, but I'll be doggoned if I get mold in my daughters pool in the summer. Or on any of the various toys that sit in the water.

Dosing the water with chlorine or bleach or even star-san may help, but if the room is damp (like most basements) I'd be willing to bet that the mold comes back.

Adding bleach to the water may or may not do the trick - remember that the chlorine will gas off in a short period of time.. And your green shirt would stop being green.

I had the same issue, and stopped using a shirt. To compensate for losing the heat sink effect of the shirt, you can keep the water level in your bucket equal to or a half inch greater than the level of beer in your fermenter. I actually like to float it a little - the cool water being under the fermenter as well can only improve the efficiency of the operation.

That said, one of the best beers I've made so far DID have mold all over the bucket, and INSIDE at the krausen ring.. Soo... Maybe it's not such a bad thing?

Well, kegged today. Hydro sample tasted different to what I expected... not bad, just way sweeter (maltier?).

Here's a pic of the insides when I opened:

And hydro sample:


Thanks for all the suggestions. I actually do have a fan that I use, but it was off for a while so stale air could've been a problem.

I'm avoiding the shirt thing for a while, I don't know if it adds enough value to be worth the risk of mold again.

wyzazz said:

Keeping the ambient air drier (dehumidifier) should keep the mold down. I realize it's sitting in a tub of water, but I'll be doggoned if I get mold in my daughters pool in the summer. Or on any of the various toys that sit in the water.

Dosing the water with chlorine or bleach or even star-san may help, but if the room is damp (like most basements) I'd be willing to bet that the mold comes back.

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These are just my opinions and in no way are meant to denounce or repudiate someone elses views:

IMHO: The mold is caused by the shirt being wicked with water from the tub and no air movement under the shirt leading to conditions that promote the growth potential. Bleach, Vinegar or Starsan will indeed evaporate or disapate over time, but will be wicked up with the water into the shirt which will inhibit (notice I did not say "STOP") the growth of mold. In addition, changing the shirt periodically can reduce or possibly eliminate molding conditions.

Ever seen the bottom or sides of a boat left sitting in the water for an extended period of time? All kinds of stuff will eventually grow when left alone, if the water and other surfaces are not treated (such as chlorine, bleach or some other agent) properly.

Salute!

It looks like in the end you made good beer. I think the fan idea would be a good idea plust it would help in cooling further.

I don't think the mold is much of a concern as long as you clean the outside of the fermenter before opening it up & minimize the contact time to the open air. You made beer in the end, I think that's what is most important!

I have a similar mold concern with my water bath setup. I don't use a t-shirt, but use a temp-controlled cooler with the lid closed except for a crack (to let CO2 out but still help my chilling unit maintain temp). I use starsan in the water, but above the water, where the bucket is exposed, there is mold growth regardless of how clean the bucket is when I start. I periodically check it and try to spray it down with isopropanol and wipe it off, but there's always some mold under the lip of the lid which really worries me, since it's hard (impossible) to get it out (even just before opening it for bottling).

If I find a solution I'll post it, but right now I just do the best I can to wipe it off and sanitize it periodically and thoroughly sanitize it before opening for bottling.

Maybe some damprid (CaCl2) suspended above the water would help (maybe with a fan)...