If you’ve been fermenting vegetables for a while then you’ve probably faced a shock discovery. You’ve cut or shredded your vegetables, added salt or brine, submerged them in said brine, and then left them to ferment.

Then a day or more later you opened your jar to find, much to your horror, a white film of mold. Or, worse yet, a big hairy mold patch of varying colors.

You’re probably heartbroken, or at least disappointed. You may assume that all of that time and money you put into those vegetables you were fermenting was wasted.

What to do With A Moldy Ferment

If you opened your jar or vessel up to find a layer of mold on top don’t panic. You may be able to easily dispose of this and have perfectly good fermented vegetables below the brine.

Lacto-fermentation is an anaerobic process meaning it must be in an oxygen-free environment for it to happen properly and fully. Any oxygen put into the mix can cause unwelcome microorganisms such as mold or yeasts.

So while your vegetables may be happily fermenting under the brine, the surface of the brine is still exposed to oxygen if you are using a jar or open-crock method of fermentation. This is common, though, and it was very common in times past to simply go to the cellar to check on the ferments, scrape any growth off the surface, and retrieve the fermented vegetables below.

Factors That May Contribute to Mold Growth

If you are experiencing a mold epidemic of sorts in your ferments then their maybe something more at play than what we spoke of above. You may want to think about the following circumstances:

Fermentation Temperature

Ferments like sourdough and yogurt might prefer a warmer temperature of 80 or 110 degrees, respectively, but vegetable ferments, in general, prefer a cooler temperature. This makes it especially difficult when you are attempting to preserve at the peak of the growing season, which is most likely the hottest time of the year.

So try to find a cool place to ferment your vegetables. A root cellar is ideal, and traditional, but a cool basement or garage is also helpful. Or just find the coolest place in your home. A temperature of 65 - 80 degrees is your best bet in avoiding mold.

Vegetable Submersion

Probably the most important factor in lactic acid fermentation is the submersion of the vegetables underneath the brine. Lacto-fermentation is an anaerobic process, meaning it requires a no-oxygen environment.

If you are experiencing mold problems check to make sure your ferment is under the brine. If it is not then you will need to weight the vegetables down with a clean rock or weight, a regular mouth lid inside of a wide-mouth jar, or brine inside of a plastic baggie.

Salt Content

The purpose of salt in a lacto-ferment is to inhibit the growth of undesirable pathogens including molds and other microorganisms. Too much salt won’t allow lactic acid fermentation to occur fully, but too little salt can result in off flavors or mushy vegetables.

Likewise, too little salt will not preserve the food between the start of fermentation and when the lactic acid bacteria begin to proliferate and create an acidic environment. This can lead to mold more readily taking hold of your ferment.

Introduction of Starter Culture

The introduction of an already established starter culture can help prevent unwelcome pathogens from taking hold of your ferment before the lactic acid bacteria have a chance to form.

You can use whey or a starter culture in these circumstances for a little extra insurance.

Bad Microorganisms Present on Your Vegetables

Finally, consider the vegetables themselves. Are they in a state of decay? Did you wait too long to get them fermented? Were they sprayed with chemicals that may interfere with the natural fermentation process?

If any of these are a factor then you may want to consider using only fresh, organic produce in your ferments if you have access to them.

In conclusion, mold occurring above the brine is a fairly normal part of fermentation, but anything out of the ordinary may be caused by a number of non-ideal situations for your ferments.

In This Article:

• What to Do with a Moldy Ferment
  
• Factors that may Contribute to Growth
  

Related Articles & Recipes:

• Fermented Vegetable Expert Advice Articles, How-to Videos and Recipes
• Salt vs. Whey vs. Starter Cultures
• Choosing Fermenting Equipment
  
• Sauerkraut Recipe
  
• Cultured Carrot Sticks
  
• Naturally Pickled Green Beans
  

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