Mold: What You DON'T Want to See on Your Ferments! Tips for Preventing It for Delicious Veggies Every Time

This article is about how to prevent mold and fungus growing on your lacto-fermented vegetables and other ferments. And if you do happen to get a bit of mold, find out what to do about it!

We all have the best intentions...but sometimes it's just easier to take a shortcut...like I did recently in one of my jars of fermented tomatoes.  If you've been fermenting anything for awhile, then you know that you must keep the vegetables beneath the surface of the brine (liquid).  

Otherwise you do take the chance that mold may form.  I've successfully been able to avoid this up til now.  I've gotten pretty creative with ways to weigh down my ferments, but once in awhile some vegetable matter will pop up slightly above the surface.  It's been no biggie...up til now! 

Find out how to ferment your vegetables so you don’t grow mold instead of healthy probiotics!

FTC Disclosure: There are affiliate links scattered throughout this article. If you click through and make any kind of purchase, I may earn a small commission at no extra cost to you.

SCARY MUSIC PLAYS:

"NOOOOOOOO!!!!!!" I shriek!!!!

"NOOOOOOOO!!!!!!" I shriek!!!!

That ugly monster you see in the picture above is a combination of black and white molds.  You just DON'T want to see any kind of mold on the surface of your ferments.  Black, white, green....doesn't matter.  It's all bad.  

Some hard core fermenters say to just scrape it off and go ahead and use it.  I say....Don't take the chance.  Especially if you are feeding children or the elderly or those with compromised immune systems....it's better to just dump the batch into the compost pile, and start fresh.

 I have no idea if this is true, but I have read that the mold spores can even be found at the bottom of the liquid....so this mama is NOT taking the chance.  

I got lucky with all those half-gallon jars of fermented tomatoes happily bubbling and frothing away on my counter....except for this one.  That tomato you see there bobbed its way to just above the surface...and WHAM! POW! BOP!  The mold got it! 

NOTE: I realize many reputable old-time fermenters, including my hero, Sandor Katz, encourages just scraping off the mold. I’ve heard it’s good. I’ve heard it’s bad. I’m just very careful, so if you want to just scrape it off, feel free!

How to Avoid Mold in the First Place 

There are some things you should be doing with your lacto-fermented foods to avoid growing potentially dangerous mold on top….and then throughout. Here’s a great list:

1) Weigh Down Your Veggies

Keeping your vegetables below the surface of the brine is SO vital to a healthy, unadulterated ferment. Unfortunately, vegetables like to float, especially those little bits. You have to simply find a way to weigh them down so they stay below the surface of the brine.

Here are some of the ways to “weigh” down your veggies in your lacto-ferments.

I've gotten pretty creative with some of my ferments. I've used boiled rocks.....

Some of the "weights" I've used in my ferments.....

Some of the "weights" I've used in my ferments.....

The rocks are actually some of my favorite things to use.  You just find good size rocks that will fit inside the jar top, press them down until they are forcing the vegetables under the liquid...and that's it!  Plus, they’re FREE!

The other weights I like to use are the ceramic or glass discs. Some have a little hole, and some don't.  It doesn't matter either way. They fit perfectly inside a wide-mouth Mason Jar, and press down the veggies.  The problem is if you are using a wider-mouth jar, you may need two or even three of them!  

They are not expensive, either.  You can find these ferment weights here.  

Finally, you can use a smaller glass jar that fits inside the mouth of the larger jar.  Just push it down and let some of the liquid into it.  There is NO way that baby veggie is going to be coming up for some air!  This is also free (except for the cost of the smaller jars).  I use the tiny Mason sauce jars.  

Pressing the small (4 oz) jelly jar into the brine...also pressing down the veggies.

Pressing the small (4 oz) jelly jar into the brine...also pressing down the veggies.

2) Your Brine Needs to be Strong Enough

The liquid you use in your lacto-fermented formulations is so important…in fact, it’s vital to the health and strength of your fermented vegetables. You need to add some salt to the filtered water to create your brine.

Typically, your brine should range from a minimum of 1.5 percent to 3% salt by weight. Different vegetables require slightly different percentages of salt. It seems that 2-3% is that nice sweet spot for most vegetables. I usually shoot for about 2% salt in my liquid.

The salt inhibits the growth of any “bad” micro-organisms or pathogens and doesn’t affect the good ones (lacto-bacilli). The issue many people have is the amount of salt this takes because they may be watching their salt intake…or perhaps they just don’t like all the salt.

Rest assured, your fermented foods taste delightful, even with the salt. Also, I’ve found drinking enough water and getting rid of all processed foods really alleviates the need to be too watchful about the salt content in the little bit of fermented foods most of us eat daily.

Your salt needs to be measured out by weight because different salts weigh different amounts. That mineral rich salt from the Dead Sea may weight significantly more than that finely ground kosher salt. The best thing to do is go to a brine calculator so your salt is fairly accurate.

Now, with all that said, I usually just “eyeball” and “taste” my brine. I know this isn’t a great habit, but I’m being honest. I’ve found that if I add approximately 2 tablespoons mineral rich natural salt to my quart of fermented veggies, things turn out just fine.

But do be sure to take a look at more information on this for yourself, as well as check out a brine calculator.

Fermented beets require a bit more salt than softer veggies, like zucchini.

Fermented beets require a bit more salt than softer veggies, like zucchini.

Salt Percentages for Different Vegetable Ferments

Let’s go a quick step further with a short list of percentages as a guideline for your own fermented vegetables:

Typical vegetables like cabbage (sauerkraut) do well in a 2% brine solution.

More firm vegetables like carrots, beets, asparagus, green beans, etc. enjoy a 3% brine solution. The additional salt helps break down the fibers for a more successful and delicious ferment!

“Watery” vegetables such as cucumbers, peppers should be fermented at up to a 5% solution.

Very high level brines, up to 10%, are for some foods, although these are specialty items, generally, and not the typical lacto-ferment I’m talking about in this article. Some foods that require a much higher percentage of salt include feta cheese, olives, etc.

Some vegetables, including salsa-type ferments, are “dry-brined.” This means they don’t have water added to them if the salt can help the vegetable release enough of their own juices to make enough liquid. This type of solution is very common in sauerkrauts and salsas with tomatoes. The resulting salt solution should be around 2% to 5%.

The salt in the ferment definitely helps kill off the bad guys, leaving your lacto-bacilli happy and ready to ferment your vegetables.

Final Thoughts on Keeping Mold Out of Your Fermented Foods

Honestly, fermentation is really quite simple!

I realize some people are hesitant to try fermenting foods. Reasons I’ve heard is that 1) It’s gross (it is the beginning stage of the decomposition process, after all); 2) They’re afraid they’re going to kill themselves; 3) Fear of failure; and others.

Really, don’t be afraid! It’s not weird! Or gross.

Fermentation is a traditional food preservation that is worth getting to know and do for a number of reasons, such as your health, self-sufficiency, and the super fun science of the process!

What do you think of fermenting your veggies? I’d love to know!

You may also enjoy these related fermentation articles:

What is THAT Living in Your Kombucha SCOBY?

Golden Beet Kvass…SO Delicious and Easy

Fermented Asparagus: A How-To Tutorial

And there are many more on the website at Healing Harvest Homestead!

I’d love if you’d leave comments, questions, etc.

Hugs, Health, & Self-Reliance!

Heidi

P.S.  I hope you‘ll get the newsletter and never miss a thing! You’ll also get immediate access to the Resource Library, filled with more self-sufficiency topics that are downloadable and printable for you! 

Just complete the form below:

Fermentation as a food preservation method is awesome! It’s healthy, fun, and it works…..Except for when it doesn’t. Mold is a sign of a failed ferment. Here is how to avoid mold on your fermented vegetables, ruining them. You can avoid mold easily …

Fermentation as a food preservation method is awesome! It’s healthy, fun, and it works…..Except for when it doesn’t. Mold is a sign of a failed ferment. Here is how to avoid mold on your fermented vegetables, ruining them. You can avoid mold easily following these tips! #moldy #ferments #fermentation #howto #avoidmold #tips #whyyoushould #allabout #recipes #ideas #healingharvesthomestead