The sour (fermented) pickle recipe that I am following states:

Check the crock every day. Skim any mold from the surface, but don’t worry if you can’t get it all. If there’s mold, be sure to rinse the plate and weight.

The only change that I have made to the recipe is to add 3 med tomatoes along with 4 lbs of cucumbers.

The pickles do seem to have more surface mold than sauerkraut. However, is there any real advantage to skimming the mold off of the top? It seems that if the mold is aerobic and restricted to the surface, then any skimming, especially if combined with removing the stone weight on top of the pickles, would simultaneously mix both mold and air in.

I would prefer to skip skimming every day, and the shape of my crock makes it somewhat awkward to do: the crock curves in at the top, and there is < 1 cm of brine between the surface and the stone weight.

Is there any disadvantage to not skimming every day?

  • Never made pickles, so I don't know if the name is accurate. But if it is really a mold, chances are it produces toxins, which end up in the brine.
    – rumtscho
    Oct 12, 2011 at 13:27
  • 1
    @rumtscho according to the NC Cooperative Extension a white scum on the top is a harmless yeast and/or fungus. The presence of harmful molds is indicated If the pickles themselves become slippery. Oct 12, 2011 at 14:10
  • Is that 'tomatoes' tag accurate?
    – Katey HW
    Oct 12, 2011 at 19:45
  • @KateyΨ yes, I put a few green tomatoes in the crock. Oct 12, 2011 at 19:47
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    Oh okay - I am not familiar with this kind of pickling (my grandmother is the queen of bread and butter pickles) but maybe mention that in the question? I am not sure if the acidity of the tomatoes affects anything notably, and I can see other people having the same confusion.
    – Katey HW
    Oct 12, 2011 at 19:51

2 Answers 2


I make pickles similarly, but not quite the same way: I usually make half-sours, as even the 5.6% salinity of that recipe would be way too salty for my family's tastes. I boil the brine before using it, letting it cool before adding it to the cucumbers. I use a clear glass jar rather than something opaque like stoneware, which might change the mechanics a bit. The biggest difference, though, is that I add a slice of bread, which really gives the fermentation a head start. Usually, the pickles are ready in two days, three at most. Perhaps it's this shortened time period, but I've never encountered any scum that needs to be skimmed off. Sometimes, if it was a particularly hot day or something, there will be mold, either on the bread or on the liquid; if this happens, the pickles are thrown away — it's just not worth the risk.

That said, scum does not equal mold. If it's anything other than white, and/or if it's fuzzy, it's mold, and I personally would not eat whatever it occurred on, unless of course it was rotten moldy milk blue cheese. If it's really just scum, then it's probably a cosmetic issue: if you don't skim it off, the brine might turn cloudy and unappetizing.


From what I've read, leaving the scum on reduces the salinity of the brine, which changes fermentation. Skim the scum so that the salt level stays the same ... check out "Wild Fermentation by Sandor Katz.

  • this seems implausible; I have about 10 liters of brine and <50ml (0.5%) of scum. I have read Katz' fist book and am looking forward to reading his latest "The Art of fermentation" Aug 5, 2012 at 2:34

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