Is it necessary to skim the scum off of fermenting pickles? 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 &lt; 1 cm of brine between the surface and the stone weight.

Is there any disadvantage to not skimming every day?
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.