Fermentation Support Forum

If mold is caused by spores, and the sauerkraut is fermented in a mason jar with tight fitting lid, where do the spores come from that sometimes cause surface mold?

They're in the air EVERYWHERE...unless you have a good HEPA filter running. Even then there are likely mold spores on the surface of veggies and fruits.

Thank you, Tim. I have learned so much already from this website.

Denise, really the trick is to keep things clean (not sterile) and provide a frementing environment in which the good bugs will quickly out-compete the 'bad.' Sanitizing/sterilizing things is really overkill, and just to be clear, I'm not suggesting you get a HEPA filter.

Fungi (mold) needs lots of oxygen to grow, and most molds grow on the surface of things where oxygen is abundant. It might actually serve you well to stir your ferment once, after it gets started...this will submerge the [inevitable] mold spores where they can't get easy access to oxygen, where they're competing directly with good bacteria, preventing them from turning to mold, producing mycotoxins, making your kraut look like it needs a shave, etc.

All bacteria and fungi produce what are called, in scientific terminology, 'competetive factors.' Lactobacillus produces lactic acid and hydrogen peroxide that is lethal to mold spores. The faster the Lactobacillus takes hold, the less likely you'll have mold. And a perfectly sterile environment is not good for the bacteria, just like it's not good for the mold.

Thank you, again, Tim. I am understanding more how this fermentation process works.

Holy cow, Tim, THAT is one informative post! THANK YOU from this fermentation 'newb'! =)

Tim Hall wrote:Denise, really the trick is to keep things clean (not sterile) and provide a frementing environment in which the good bugs will quickly out-compete the 'bad.' Sanitizing/sterilizing things is really overkill, and just to be clear, I'm not suggesting you get a HEPA filter.

Fungi (mold) needs lots of oxygen to grow, and most molds grow on the surface of things where oxygen is abundant. It might actually serve you well to stir your ferment once, after it gets started...this will submerge the [inevitable] mold spores where they can't get easy access to oxygen, where they're competing directly with good bacteria, preventing them from turning to mold, producing mycotoxins, making your kraut look like it needs a shave, etc.

All bacteria and fungi produce what are called, in scientific terminology, 'competetive factors.' Lactobacillus produces lactic acid and hydrogen peroxide that is lethal to mold spores. The faster the Lactobacillus takes hold, the less likely you'll have mold. And a perfectly sterile environment is not good for the bacteria, just like it's not good for the mold.

I agree with MarciGal. My fermentation has become so much easier applying Tim's advice. And so far, no mold!!!

In the case I would ever get mold, I now know, from this site, to simply skim it off. So simple.

If I may revive an older thread...

I think I may be too worried about scum formation. I was concerned that even if I skimmed it off the top, I couldn't get it all, and some of it might get into my kraut or veggies, or as I pulled the kraut out of the jar, it would come in contact with some of it.

However, I realize that the ferment is inhospitable to mold, so it wouldn't be able to take hold and grow. And if I happened to ingest a bit of it, b/c I couldn't get it all skimmed off, how bad could it be? After all, the mold spores are on the surface of fruits and veggies. Take a bite of an apple, and you're probably eating mold spores, but they aren't in large amounts.

So, maybe I won't worry so much, but I'll still use my airlocks and cover my jars. :-)

When I was growing up, my dad made pickled corn quite a bit in buckets that he'd keep down in the cellar. I was going to try a piece until he told me he had to lift up an edge of the "carpet" to get at the corn.

woolyprimate:

I recall my mother (born in 1916) telling me that when she was a little girl, her grandpa would make sauerkraut and leave it on the step (the steps that go down to the outside door). She would see that sauerkraut and want some. She would pull back the surface mold to make an opening for her hand to get into the crock, and reach in and grab a handful and pull it out. Yum, she said. She is not alive now, so I can't ask her any details. Seems like surface mold on sauerkraut is a normal thing.

I enjoyed reading your post with your logic about how safe the sauerkraut is, even with surface mold.

The only real mold I ever got was when I was trying to ferment in a plastic bucket. I've had a couple little suspicious looking dots on the top, but I picked them off and never really had a problem.

I think that the idea of mold has become so frightening to us (My generation) that we aren't willing to taste and decide anymore. My kimchi looked a little different a couple days ago with white spots on some of the veggies. It also smelled different, but not BAD. I gave it a taste and it was really good so I gave it a stir and put it in the fridge. I haven't gotten sick from it and if anyone would - it would be me. In fact I've never gotten sick from ANY fermented product.