Musty Saurkraut

I am no fermenting expert, but have made saurkraut a couple of times now, and make Kvass regularly. I just finished a large batch of kraut. It was my first time fermenting in a crock and I made some mistakes. Namely, not having enough weight on top, and allowing the brine to evaporate below the cabbage briefly in the beginning. I also think it was a bit too warm (mid-high 60s). Anyway a couple weeks in to the ferment a small amount of mold formed. I skimmed and made sure all cabbage was below the brine. Then at the end of the ferment (about 4 weeks) I skimmed again, and started putting the kraut into jars. Unfortunately I got interrupted and had to come back and finish the job a couple of days later. (I replaced the weights and made sure everything was under the brine in between). At that point a nice bloom of mold had formed on the surface, but was very easy to remove. I continued jaring the rest of the kraut. There was no mold or discoloration in the cabbage, and once the mold was removed it smelled very krauty, not like mold at all. However, the jar I most recently opened to eat from has a subtle musty flavor. It smells like kraut and mostly tastes like kraut, but there is just a tinge of must/mold taste. I am wondering if some mold got mixed into the kraut and if it’s a concern? Will it get worse while stored in the fridge? Any way to remove it? I have 12 quart jars so I’d hate to throw it out, but also hate to eat it if it’s not actually nutritious.

Any advice is appreciated!

Eloise, I don't fancy being the bearer of bad news, but...
If mold starts growing on anything you preserve, it sends spores or "roots" to the whole batch. So yours should be thrown away.  The entire batch is infested.

Next time, overdo the liquid if you are not able to babysit the batch.
I feel for you! I spend half of my time in my city apartment and half at my farm. I never have the time to look after my sourdough, kombucha, sprouting seeds, or fermenting. Everything goes awol when my schedules change 😪

Thanks for your reply!

I guess I am confused by your advise because I have read of mold being common (floating on top the brine) and most often not a concern. This is one of many articles I referenced in making my decision not to throw the batch at the first signs of mold.

https://nwedible.com/ack-my-sauerkraut-has-mold-on-it/

Here is another.

https://fermentedfoodinfo.com/is-sauerkraut-mold-bad-for-you/

The mold on my batch looked much like that pictures in the first article, And many other articles/photos I referenced when I first discovered it.

I know that mold can definitely be harmful but that not all are, and most of what a saw was leading me to think that this mold was harmless.
Would your opinion be that all molds are harmful? How do you determine what is/isn’t in your ferments?

Thanks!

I will definitely be adding more liquid in the future, and modifying my weights to be more affective!

have you tried any of the other jars? Ours sometimes gets musty... we still eat it. Sometimes we take the top layer off of the sauerkraut, and discard it.

Yes the first jar we ate was not musty. We are on the 2nd jar now. Honestly it seems like it’s become less musty as the jar has been open longer. I wonder if being sealed up made it more pronounced? It is still there but hardly noticeable even when I’m looking for it. I opened a third jar today to compare and that one seemed stronger, more like when we first opened the 2nd jar.

I guess I’m not sure if discarding the top layer would do anything, as it looks, smells, and tastes just like the rest of it from what I can tell. But maybe it’s worth a shot..

I've thrown out more sauerkraut than I've kept. I'm not really happy about that, but it has been a learning process.

I'm very cautious with fermentation. For me if everything looks, smells, and tastes good then I keep it. If any of the three is off, I discard.

Temperature management has been trickiest for me, since we have highly variable indoor temperatures and humidity here. But I also haven't added brine in the past, just used what the cabbage put out. Next time I make a batch I intend to add brine and more weight.

Eloise, was the mold you mentioned actual mold colonies with spores or was it kahm yeast? Kahm is harmless and usually shows up on the surface of the ferment as white specks. These can be skimmed off.

I've had jars go moldy and they were obvious colonies of colored mold with spores and all. The odor is distinctive and as was mentioned, impacts the whole jar with the odor and taste. I had to toss those in the compost. Do the jars smell moldy or just funky? If moldy, I would toss them since that flavor is so unpleasant and I don't want to eat that type of mold.

If I think that a batch is not quite up to par for storage, I will add a tablespoon of rice vinegar and more salt (only if needed) to keep the pH and salt levels where I want them. I use rice vinegar since it seems to impart the least flavor to the ferment. I don't always want apple cider vinegar flavored pickles.

I agree with Robin. The white or maybe grayish film that often forms on top of fermentations doesn’t usually impact the flavor of the rest of it. I think this is “Kahm yeast” but people often call it mold. Other molds are a different story, though. In my house anything fermented in the basement, unless I use an airlock gets filaments of black mold and has a musty basement taste like you describe. I don’t know if it is harmful, but if it tastes bad, chuck it.  I’ve also heard that mold indicates high ph, so possibly not the right environment for a healthy ferment.

Hmmm. Thank you all for your input! I am thinking it was mold (on the surface of the brine during ferment) and not kham yeast... it has not created any ill affects in us, but I’m not sure yet what I’ll do... I read that some molds can grow on the surface of the brine where there is oxygen, like mine had, but that it cannot survive under the brine, so theoretically any remnants of it would be killed by being mixed into the saurkraut/brine. Which it all would be now. But still not sure how I feel about it...

From a German,

Granny's Sauerkraut was always "moldy" BUT it was white yeast.

Any blue and green growth mean's ready to compost, she would not even feed it to the pigs after heating it up.

Its not only on Sauerkraut but it was also on her fermented Cucumbers...

I agree with Kaarina. If you kept it all under brine, no interruptions, etc, then you can be a bit more confident. Because there were some unscheduled events, I would assume it got contaminated.
In my experience fermenting all the things, kahm yeast is pretty easy to see (white, filmy) compared to other mold (often pink, in my ferments, or brown or green, with more obvious spores). I haven't seen it show up on a cabbage sauerkraut initially (later on as it gets older, yes). I generally ignore it.

You said

I read that some molds can grow on the surface of the brine where there is oxygen, like mine had, but that it cannot survive under the brine, so theoretically any remnants of it would be killed by being mixed into the saurkraut/brine. Which it all would be now. But still not sure how I feel about it...

It won't survive and grow any more, but it will still be there, along with whatever toxins and ick it produces. I'd chuck it and start again.

Thanks for the help guys. These last few posts helped clarify when/how mold is to be tolerated and when not to. I’m going to pitch it and start again. Lesson learned!