Find Your Fermentation System

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Photo by Amy Grisak

When I stepped into the world of fermentation 20 years ago, I had no desire to slice up 50 heads of cabbage for a 20-gallon batch of sauerkraut. Although that’s how my great-grandmother made sauerkraut in her basement, I set out to find options for creating smaller amounts. Not only did the reasonably sized recipes I found allow me to experiment more, but when it was just me eating the resulting ferments, I wasn’t ‘krauted out.

The main goals in vegetable fermentation are to keep the food below the brine (minimizing oxygen contact), and to prevent insects from finding their way into the ferment. After trying many different airlocks and fermentation systems, I’ve discovered what works well for various foods and batch sizes. Here are the methods I’ve tried, and the pros and cons I’ve uncovered with each system.

Water-Seal Crocks  

My great-grandmother used a crock, making it my first choice during my early days of fermentation. Sticking with tradition seemed safer. My big purchase was a Harsch crock, a European-style crock with stone weights and a lip that forms a water airlock. While Harsch crocks aren’t made anymore, several similar designs are available from other manufacturers that function the same way.

Water-seal crock (pictured) and Kraut Source units both rely on water airlocks to work.
Photo by Amy Grisak

Pros. The beautiful ceramic crock is a nod to tradition. It feels good working with this natural material, and I like that no plastic touches my food. The stone weights work well to keep the vegetables submerged below the brine. This type of crock is ideal for a batch of New York-style whole pickles, and the water airlock is terrific, if you can resist checking the vegetables.

Cons. Crocks are heavy and can be difficult to store. Even though my crock is only 5 liters, it’s not easy to move, especially when filled. (I still have to ferment large batches to make dragging it out worthwhile.) If you want to open the lid and check on what’s fermenting, you’ll disrupt the airlock. Crocks are pricey; less expensive options do exist, but it’s common to pay more than $100.

Summary. These European-style crocks are an excellent option for those who wish to make large batches that don’t need to be checked during the fermentation process. If you wish to make larger batches and check them more regularly, it’s easy enough, and less expensive, to use a standard crock and place a plate and weight on top of the vegetables to submerge them. Be sure to drape a towel over the top to keep out insects.

Kraut Source

Because I was already familiar with a water airlock system, this small-scale option caught my eye. Instead of stone weights, Kraut Source (available below) uses a stainless steel plunger to keep vegetables under the brine. The plunger fits perfectly in a wide-mouthed jar, and it prevents vegetable bits from floating to the surface.

Kraut Source  
Photo by Amy Grisak

Pros. It’s ideal for small batches; all you need is a wide-mouthed jar. The water airlock system keeps oxygen out completely, as long as you don’t peek.

Cons. It has multiple pieces, which means more items to store and keep track of. I’m likely to toss these types of things into a kitchen jar and lose a piece. With a multipart system like this, I have to make sure everything goes back in its box.

Summary. Like the water-seal crocks, this system effectively keeps oxygen away from vegetables, unless you open the lid, in which case there’s a tendency for mold growth. If you like the water airlock systems, and you know roughly how long you need to ferment your recipes, this is a foolproof option. It’s pricier than some of the other small-scale options, with one unit costing about $30.

Silicone Waterless Airlock Lid

A friend introduced me to this method while showing me how to make her kimchi. The silicone lids are designed with a bubble on top, and when air builds up during the fermentation process, it’s released through a small slit in the bubble. The waterless airlock (or one-way valve) is designed to prevent oxygen from getting inside the jar.

Silicon waterless airlock lids and other waterless systems use a one-way valve.
Photo by Amy Grisak

Pros. The silicone lids are lightweight, easy to clean, and nearly indestructible. You can put the whole jar, including the lid, in the refrigerator when the fermentation processed is finished, which is nice, since some ferments will continue to bubble away.

Cons. You’ll need a weight to hold vegetables under the brine. Glass weights work best, but you’ll have to purchase them separately. Although these lid valves are designed to be one-way, you might still have issues with oxygen reaching bits of floating vegetables, causing mold to form.

Summary. These lids are easy to use and clean, and they’re inexpensive. (Prices vary, but options are available for less than $10.) The most challenging aspect is finding a way to keep the vegetables below the brine. Before buying glass weights, I used an onion slice or cabbage leaves, but neither kept everything in place. Even when using a weight, you’ll still want to use something to prevent small bits of vegetables from floating past the weight to the surface.

Double Jars 

Sometimes, simple is the best way to go. On the recommendation of a veteran fermenter friend, I experimented with jars by placing a smaller jar inside of a larger one to hold down the vegetables. It’s simple and inexpensive, and it works. You’ll need wide-mouthed quart or pint jars to hold the vegetables and brine, and regular pint or half-pint jars filled with water to act as weights. You’ll also want some sort of covering, either a light towel or cheesecloth, to keep insects from finding their way into the ferment.

Double jars
Photo by Amy Grisak

Pros. Most people have jars on hand, making this an inexpensive option that’s ideal for small batches.

Cons. It’s not as attractive as other methods, and it can be messy, particularly if the brine bubbles over the top. If left uncovered, flies and other insects can get into the mix.  

Summary. If you want to try countertop fermentation but you don’t have any equipment, this is a simple and effective method. It’s not as pretty as some methods, and I’ve found that once I fill the jars, I need to leave them in place. (I tend to spill the brine if I have to shift them to a new location.) Plus, you’ll need to cover the jars. While we joke about flies adding extra protein, bugs in the brine will ruin the batch.

Spring Plunger with Waterless Airlock Lid

This is a simple design consisting of a spring and plunger held down by a vented lid. All you have to do is add your vegetables to a jar, pour brine over top (if necessary), insert the spring and plunger, and then screw on the lid.

Double jars and spring plungers (pictured) are both simple and inexpensive options.
Photo by Amy Grisak

Pros. This system is simple to use, and it doesn’t require a weight. The lids and springs are inexpensive, and you usually get two or more in a kit. (Ball sells kits for less than $10. Other options are available for less than $20.)

Cons.The plunger isn’t solid like it is in the Kraut Source system, so small pieces of vegetable can float to the top.

Summary. Unless you’re using this system for larger, chunkier vegetables, it’s helpful to use a piece of cabbage leaf or a slice of onion to keep the vegetables under the brine. When I fermented grated carrots, I had to skim off the carrot bits that floated to the surface to prevent them from molding. When I opened up the jar to taste the carrots a week through the fermentation process, I had to pick out the floating bits then too, before screwing the lid back on the jar.

Vacuum Pump with Waterless Airlock Lid

Brillenti Easy Grip Fermenting Lids are the latest addition to my fermentation arsenal. This system and others like it come with an oxygen vacuum pump and lids with a one-way valve. While I typically don’t like extra gadgets, the pump works great to remove air after testing a ferment. It’s fun to watch the bubbles rise as it pulls air from the jar. With other methods, I often saw white mold on top within a few days of removing the lid to sample the vegetables. This doesn’t happen with the vacuum pump.

A vacuum pump can pull air out of a jar that’s been opened mid-fermentation, eliminating the risk of mold growth on floating vegetable bits.
Photo by Amy Grisak

Pros. The ability to pull out oxygen after tasting is a game changer. The Brillenti lids also include a date tracker that you can set when you start a ferment, which is handy when I have a line of fermenting goodies on the countertop.

Cons. The lids can be difficult to unscrew, although running them under warm water helps. You’ll also need a weight to keep the vegetables below the brine.

Photo by Amy Grisak

Summary. Vacuum pump systems can be a bit pricey upfront (the Brillenti system sells for $35), although most come with multiple lids. If you like to check on your ferments periodically, a pump will virtually eliminate the risk of mold.

A System to Suit Your Style

With so many options out there, it can be overwhelming to figure out which fermentation system works best for you. The good news is that you really can’t go wrong. Some setups are a little more foolproof than others, but as long as the vegetables stay below the brine, it’s mostly a matter of what gear suits your style.

Amy Grisak is a freelance writer who’s been avidly gardening for decades. She lives in Great Falls, Montana, where she has a penchant for making delicious dishes from the vegetables she grows in her garden. See more of her work at Amy Grisak

Kraut Source Fermentation Kit

This fermentation kit has everything you need to ferment sauerkraut, kimchi, pickles, and more, right in your own home. Whether you’ve been fermenting for years or are just getting started, this kit makes fermentation easy, with just a Mason jar and a special gasket tool, all in compostable packaging. This product is available at the MOTHER EARTH NEWS store or by calling 800-234-3368.  Item #10607.

Take Your Fermentation Skills Beyond the Basics

Learn the ins and outs of fermentation from the experts at the Noma restaurant! With more than 500 step-by-step photographs and illustrations, and 100 approachably written and meticulously tested recipes, this book takes readers far beyond typical kimchi and sauerkraut to include koji, shoyus, misos, and more. This title is available at the MOTHER EARTH NEWS store or by calling 800-234-3368. Item #9291.


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