Tips for Preventing Mold in your Ferments

My first few attempts at making sauerkraut resulted in a pink, moldy mess. I’ve come a long way since then, creating some delicious fermented foods for my family. If you want to try fermenting your own vegetables but the idea of poisoning your family intimidates you, read these tips for preventing mold in fermented food. This post will get you one step closer on your fermentation journey.

Fermentation is a fantastic tool for preserving food while adding health benefits at the same time. The process is very simple, and once you try it, you will find it’s quite addicting. Using tools like the airlocks and lids and weights that come with fermentools can make it even less intimidating to get started.

Although fermenting is simple, there are times when the dreaded mold happens. Mold can appear on the surface of your ferment for a variety of reasons. The tips I’ve gathered here will help ensure that the mold stays away. In my own experience, any time I get mold (which is actually pretty rare, so don’t be scared!), it’s because I didn’t follow one or more of these tips.

 Tips to Prevent Mold in Fermented Food

• Always use clean equipment. It’s not necessary to sterilize your jars, weights or lids, but they must be clean. Wash with soap and water and rinse thoroughly.

• Make sure your hands and tools are clean, too. Wash hands, knives, cutting boards and any other items you will be using.

• Use the proper brine. While some experienced fermenters experiment without salt, I personally would not even attempt it. Whenever I ferment veggies, I prepare a brine; typically using 1 to 2 tablespoons unrefined sea salt per quart of water. Click here for more details about salt and fermentation.

• Use the right airspace. When the brine and weight have been added and you are ready to put a lid on your ferment, there should be about an inch of space between the surface of the brine and the rim of the jar. If the brine rises as the veggies ferment and release liquid, you can spoon some out, or if the brine level lowers you can add a bit more to the top. Just try to maintain that inch of space; any more and bad bacteria has more room to invade.

• If using spices and herbs in your ferment, the small pieces can be hard to keep under the brine/weight. You can put the small bits in a tea bag so it will stay beneath the weight.

• Use the freshest vegetables you can find. The older the vegetables are, the more time bad bacteria has had to grow on the surface.

• If tasting your veggies mid-ferment, make sure to use a clean fork, and don’t double-dip.

• Consider using tools. Airlocks are very helpful at keeping oxygen (which mold loves) out of your jar., and weights are crucial for keeping veggies under your brine.

Don’t let mold scare you away from the wonderful world of fermenting! With just a little bit of careful preparation, and by following these tips for preventing mold in your ferments, you’ll almost always have wild and tasty success.


Andrea gardens, forages, cooks and ferments on a little plot in the city. She loves spreading the word about age-old practices and making them new, exciting and feasible for everyone. Find her at

Leave a Comment