Fermentation Crocks: The Who, What, Where, When, Why and How

Do you want to easily and effortlessly make probiotic-rich fermented foods a part of your life?

Are you confused over what container to ferment in?

Are you afraid to eat food that’s been left on your counter to ferment for weeks and is now covered in mold? I am!

Are you tired of fermenting in make-shift containers?

Read on for the Who, What, Where, Why and How of fermenting in a water-sealed ceramic crock.

And when you’re ready to make some sauerkraut, here’s my How to Make Sauerkraut In a Crock in 7 Simple Steps [Healthy, Flavorful, Easy] recipe:

WHAT is a Fermentation Crock?

A fermentation crock is a stoneware pot designed to hold cabbage and vegetables as they ferment.

There are two primary types of ceramic crocks for fermentation available: Open Crocks and Water-Sealed Crocks. Both have advantages and disadvantages to consider.

Keep in mind that sauerkraut fermentation is best done in an anaerobic (without air) environment where the lactic-acid bacteria can best do their work and yeasts and molds – that can ruin your ferment and impart an off taste – are far less likely to grow.

Open Crock

Open crocks are readily available and are what most of us envision when the word “crock” is mentioned.

This popular crock is probably what your grandmother or great-grandmother made pickles in, especially in the U.S., home to crock producing capital, Zanesville, where the Ohio Stoneware company makes both open- and water-sealed crocks. You may even have one gathering dust somewhere in your home.

To ferment in an open crock, cabbage or vegetables are first packed into the crock and then a plate is placed in the crock – to hold whatever is fermenting below the brine. Lastly, a cloth is secured over the opening. With this set-up, outside air can still enter the crock.

What About Fermenting in a Food-Grade Plastic Bucket?

A plastic bucket is a type of open crock. Not only are you allowing mold and other potentially harmful bacteria – as discussed below – into your final product, but the lactic acid produced during fermentation can react with the material in the bucket and leach harmful chemicals into your ferment. Even with BPA-free plastic, other chemicals in the plastic could leach into your foods.

Advantages of an Open Crock

Generally, less expensive than a water-sealed crock and readily available.
Open top and straight walls make it easy to clean.
Easy to fit whole or large vegetables into.

Disadvantages of an Open Crock

Ferment prone to developing surface mold and/or Kahm yeast (a harmless yeast that appears when a ferment is exposed to air).
Older crocks may contain glazes unsafe for food use, especially crocks from Mexico.
Weights and lids often need to be purchased separately and can dramatically raise the cost of the crock.
If a cloth is used to cover your ferment, it’s prone to wicking brine onto the floor.
Easy for flies and fruit flies to get into and lay eggs in (not a welcome gift in your ferment).
Makes for a frustrating fermentation experience (Just read the Comment Section on my most popular post. Has Your Fermentation Gone Bad?).

Water-Sealed Crock

A water-sealed crock is the ONLY style fermentation crock I will ferment in! Biases aside…

Water-sealed crocks are a bit more difficult to find, but as fermentation is sweeping the nation, they are starting to appear in stores and cottage industries are evolving and creating pieces of art worthy of living on your kitchen counter.

After a water-sealed crock is packed, two half-circle weights are placed into the crock to keep your ferment submerged. Then, the lid is placed into an open moat which is then filled with water. Now, outside air is prevented from entering the crock and carbon dioxide gases created during fermentation easily bubble out.

Advantages of a Water-Sealed Crock

Makes for a very easy, almost care-free fermentation experience (You have to keep the moat filled with water.).
Neither flies nor fruit flies can get into the crock and lay eggs.
Very little chance of mold or surface yeasts growing on your ferment.
Takes the guesswork out of making sauerkraut and other fermented vegetables.

Disadvantages of a Water-Sealed Crock

The water in the moat must be monitored and filled as necessary. If not, the seal will be broken and air will be allowed to flow into the crock.
Narrower opening makes it more difficult to pack your ferment.
Shape at the top of the crock, where the lid is, can make it difficult to clean.
Sealed environment makes it hard to monitor what is going on inside.
Generally, more expensive than an open crock.

WHY Use a Water-Sealed Fermentation Crock Instead of Jars?

Now that you understand the differences between open crocks and water-sealed crocks for fermentation, I’ll share with you the advantages of fermenting in a water-sealed crock over a mason jar.

I am all for fermenting in mason jars, recommend their use for making sauerkraut and ferment about a third of our family’s annual supply of sauerkraut in jars.

My teaching recipe, How to Make Sauerkraut In a Jar in 7 Simple Steps [Healthy, Flavorful, Easy] uses mason jars for a fermentation vessel. It works great for consistently fermenting mold-free sauerkraut.

However, once you’re comfortable with fermenting in a jar and want to make larger batches or just want the greater depth of flavor that develops in the more stable environment of a stoneware crock, then I recommend graduating to fermenting in a water-sealed crock.

What About Fermenting in Jars with Clamp Lids or Using Air Locks?

Many people successfully ferment in either a jar with a clampdown lid or various jars with an airlock in the lid.

I have tried fermenting in the Fido-style jars witht the clamp lids and for sauerkraut don’t find any great advantage in using these “fancy” jars over the inexpensive and readily available “Mason” or canning jar.

Using an airlock with the canning jar is a step up and there are some great choices on the market which I’m now using.

But, I want people to easily and inexpensively ferment sauerkraut. The mason jar is a great place to start.

The water-sealed fermentation crock is a great crock to graduate to once you have mastered fermenting in a jar and want to start fermenting larger quantities.

Advantages of Fermenting in a Water-Sealed Crock

The thicker stoneware wall creates a more stable fermentation temperature, resulting in sauerkraut with a greater depth of flavor.
Weights keep sauerkraut below the brine for safe and even fermentation.
The lid works with a water groove – which you keep filled with water – to form an airtight vacuum seal.
Gasses created during fermentation rise and escape via the water moat.
Brine can’t escape and overflow the vessel. Result? Sauerkraut with plenty of brine.
Odor is trapped in the crock. Music of bubbles escaping – plop, plop – but no smell.
Stable fermentation environment results in a greater range and number of beneficial bacteria.

Disadvantages of Fermenting in a Mason Jar

Brine can overflow resulting in a drier sauerkraut.
You have to loosen the lid – or don’t put it on super tight – to allow pressure to escape.
Not airtight. Air can enter the ferment.
Not always easy to find an effective “weight” to keep ferment below the brine. (A small “jelly jar” does the trick for me.)
Theoretically, a lower count of beneficial bacteria.
Inefficient if wanting to ferment a large quantity.
Odor in the home of fermenting sauerkraut.

WHO Should Use a Water-Sealed Fermentation Crock?

Anyone who wants to up the quality, depth of flavor and moisture content of their sauerkraut.

In addition, if you are struggling with severe health challenges, many recommend only eating sauerkraut that has been fermented in a truly anaerobic container – such as a water-sealed crock – where the beneficial bacteria have the optimal environment in which to grow.

For our sauerkrauts, we actually found our quality and consistency improved as we scaled up. It may be that a more vigorous fermentation is achieved with a bigger mass of vegetables and therefore bigger population of lactobacilli, or it may be due to a more successful airlock overall. – Dan Rosenberg, Real Pickles in Greenfield, Massachusetts

I want you to be successful fermenting in a crock. So, before you pull out your credit card, get comfortable first with fermenting in a jar.

Mistakes with small batches make for small losses. Success with a jar-sized ferment builds confidence and empowerment. So, first things first:

Have you made a few jars of sauerkraut using How to Make Sauerkraut In a Jar in 7 Simple Steps [Healthy, Flavorful, Easy]? Wonderful!
Do you feel comfortable making sauerkraut and do you know which flavors your household prefers?
Do you have a rough idea how much sauerkraut your family eats?

Yes, Yes and Yes! Then, let’s figure out what size crock you’ll want to purchase.

WHAT Fermentation Crock to Purchase for Your Needs?

Crocks are sized in both liters and gallons, depending on the manufacturer. I own a 5-liter, a 10-liter and a 3-gallon crock. I love them all. I use them all.

Usually, the size of the crock denotes its capacity. That is, how many quarts or liters of sauerkraut you can ferment in it. The crock is actually larger, than the size noted, to allow space for the weights, brine and expansion of the contents as it ferments. (NOTE: Harsch crock sizing is based on actual size. Keep that in mind if you own one and are trying to figure out how much cabbage you can pack in it.)

I recommend the 5-liter crock for most households. You’ll pack a 5-liter crock with about 10 pounds of cabbage and harvest anywhere from 5 to 6 quarts of sauerkraut from it. It is not too heavy to lift when full and it fits into your sink for washing.

A 10-liter crock also works great, especially for larger families. I pack it with 20 pounds of cabbage and harvest 10-12 quarts of sauerkraut from it. However, it is a struggle to lift and a little more difficult to fit in my sink for washing. But, the 12-quarts of sauerkraut it produces makes the drawbacks manageable.

If you consume what the average Korean does – 1 quart of Kimchi weekly! – you might want to consider something larger than 10 liters.

My 3-gallon (11.4-liters) crock gets filled once a year with enough cabbage and vegetables – 25 pounds worth! – to make 12-13 quarts of Sweet Garlic Sauerkraut, the family favorite. Its size makes it too heavy to move when full. So, I pack it in the same location that it will be fermenting. It is awkward to clean in most sinks

Since it’s nice to have a smaller crock to make a few flavor-packed jars of any of the many sauerkraut recipes I’ve developed, my next purchase will be this 1-gallon crock in my favorite colors.

I consider fermentation crocks to be heirloom items that I will be able to pass down through my family. May sauerkraut nourish and live on in my family – and yours – for many generations to come.

Some things to keep in mind as you consider the various styles and sizes of crocks.

Is the crock the right size for your needs? Crocks are sized all the way from 2 quarts to 40 liters. How much do you eat in a week and how often do you want to ferment?
What do you plan to ferment in your crock? Pickles, whole onions, corn-on-the-cob and other vegetables can all be fermented in your crock and may sway you on what size crock to purchase. See Ferment Your Vegetables, by Amanda Feifer for some non-sauerkraut crock recipes.
Once full, are you able to pick it up and move it around? A 5-liter crock will weigh approximately 25 pounds when full. I can easily carry it around.
My 10-liter crock weighs 35 pounds when full. Thar’s a struggle to move.
My 3 gallon, 50 pounds! I don’t move that and instead, pack it in place.
Can you fit it in your sink for washing?
Are the handles functional? For most crocks, they aren’t! Only my Harsch crock has a useful depression on the underside of the handles. Most are flat and I never feel I can get a good safe grip. So, I wait to put the lid on and carry the crock by putting my hands into the opening. A workable fix.
Do you know the reputation of the company making the crock? You want to make sure food-safe clay and glazes are being used. For me, Germany is the classic location, but I’m learning that the crocks from Poland are of a similar quality. China is another culture deeply steeped in fermentation as one of my readers recently pointed out:
“The Chinese have been using water-sealed crocks for thousands of years especially in the countryside where they are ideal as a perfect seal against insects etc. I live in Sichuan in a third tier city and I know that at least 8 out of ten families keep one or two of those crocks under the sink. They replenish the crocks with whatever vegetables are in season, from peppers to carrots etc. and rotate the crocks.”
Where do you plan to store it? If you want to keep it on your counter and use it throughout the year, do you need it to fit under your upper cabinets? Or, will you make sauerkraut seasonally and store your crock in the garage or basement?

WHERE to Buy Water-Sealed Fermentation Crocks?

When I bought my first fermentation crock back in 2002, my only choice was the German-made Harsch crock. I bought the 10-liter size and still use it to this day. Though it is no longer available, have no fear; you now have many choices!!!.

With the power of the internet and the growth in fermentation, there are many wonderful crocks to choose from. Below are currently available brands. Most can be found on Amazon – though not always at the best price – where you can drive yourself crazy reading all the reviews. All come with a 2-piece stone weight unless noted otherwise.

Shipping costs can greatly impact the cost of the crock you decide to purchase. Visit the website to determine current shipping costs. There are a few with free shipping.

Actual dimensions and weights are pulled off the internet and may not be 100% accurate. Different websites had different numbers for the same crock.

I tried to find the best prices at reputable companies and include links, with Amazon being the only affiliate links at this time. Pick the best one for your needs and enjoy making many batches of mold-free, flavor-rich sauerkraut for years to come. Most links are for the 5-liter crock. Use that link to also access other sizes.

If you live outside the US, scroll down to the Canada, Australia & New Zealand and Europe sections for a listing of companies servicing those areas.

Boleslawiec Polish Fermenting Crock

Handcrafted with the rich, abundant clay by the by local artisans in the Boleslawiec Region of Poland, the Boleslawiec Crock is crafted by those with 60 years of experience.

The quality of these Polish fermenting crocks is on par with the popular Harsch Gairtopf fermentation crocks from Germany but at a much more affordable price.

Sizes: 5-20 liters (1.3-5.3 gallons)
Glaze: Lead and Cadmium-free
Made In: Poland

Specification for a 5-liter (1.3 gallons) crock:
Height: 12.25 inches
Diameter: 10.25 inches
Weight: 14.95 pounds

NOTE: All the Boleslawiec crocks sold by Stone Creek Trading come with lead-free glass weights as an alternative to the traditional porous ceramic weights which are sold with most fermenting crocks. From their website:

“With traditional ceramic porous weights, the unglazed surface can absorb bacteria present in your ferment. When something goes wrong in the fermentation process, the bad bacteria or mold can be absorbed into the porous stones. It can be very difficult to then sanitize the porous stones. As an alternative, glass is non-porous and will not absorb anything!”

In addition to being non-porous:

“Luna Glass Crock Weights are 15% heavier than the traditional porous weights. The additional weight helps keep your ferment submerged where you want it.”

I’m excited to try a set of these. From one review: “Glass weights are great as they don’t absorb odors or stains and allow you to see food beneath.”

5-liter Crock at Stone Creek Trading Impeccable customer service. Comes with lead-free glass weights and recipes for pickles and sauerkraut. Shipping only to the US.

Schmitt Fermentation Crock

German manufactured fermentation pot. This traditional pot is suitable for almost all types of vegetables including cabbage, pumpkin, cucumber, carrots, and more. Stoneware does not require special storage or care and is neutral for all fermented vegetables.

The crock comes in a dark brown color and it is supplied complete with lid, stone weights, and instruction booklet.

Sizes: 5-10 liters (1.3-2.6 gallons) capacity
Glaze: Lead and Cadmium free
Made In: Germany

Specification for a 5-liter (1.3 gallons) crock:
Height: 10 1/2 inches
Diameter: 9 inches
Weight: 16 pounds with weights

5-Liter Crock at Lehman’s They also have a 3-gallon USA made crock.

Harvest Fiesta Fermentation Crock

Harvest Fiesta Pots are skillfully designed and made by local artisans in the Czech Republic. They are fired at temperatures over 2000 F and their heavy earthenware composition features a distinctive rich brown character with a lead and cadmium free glaze. Intended for long-term food storage, their artisanal design features an extra-wide opening, making it easy to load all of your favorite vegetables for maximum yield. Stone weights are included.

Notes from Reviews:

Emblem is a sticker that easily falls off.
Handles are easy to grab.

Sizes: 5-20 liters (1.3-5.3 gallons)
Glaze: Lead & Cadmium free
Made In: Czech Republic

Specification for a 5-liter (1.3 gallon) crock:
Height: 10 inches
Diameter: 11 inches
Weight: 11.94 pounds

5-Liter Crock at Amazon

Ohio Stoneware

I own this 3-gallon crock made by Ohio Stoneware. It is large, but I love it for those extra-big batches of sauerkraut. I think I packed 30 pounds of my Kimchi sauerkraut recipe into this crock last fall. It’s too heavy to lift when full, so I packed it right where it would be fermenting.

Sizes: 3 gallon (11.4 liters)
Glaze: No lead or harmful chemicals
Made In: USA, Ohio

Specification for a 3-gallon (11.4 liters) crock:
Height: 15 1/2 inches
Diameter: 11 inches
Weight: 21 pounds

Clean, smooth lines.
Weights are large and heavy to better hold the ferment below the brine.
Very reasonable price for this size of crock.
Walls are thinner than with most other ceramic crocks.

3-Gallon Crock from Red Hill General Store

Pressure Cooker Outlet

Art that Makes Food: Fermentation Crocks Individually Handmade by Artisans

Mark Campbell Ceramics

These crocks are wheel-thrown and made-to-order with your choice of glaze colors.

Design one to sit on your kitchen counter to daily add beauty to your home and inspire you to make sauerkraut! More about Mark Campbell Ceramics here. Be sure to check out his beautiful bowls.

LISTEN HERE to Mark discussing his business and journey into the fermentation world on The Fermentation Podcast, 40:23 minutes. Show notes include a video of him making a 1-gallon crock and his Taco Kraut recipe.

He totally gets how flavor-packed sauerkraut can dramatically and effortlessly shift the flavor of a meal which is why I’m always creating new recipes.

Sizes: 2 quarts (2 liters) and 1 gallon (3.8 liters) are the standard sizes, but will custom make other sizes
Glaze: Non-toxic, food safe
Made In: USA, California (Shipped worldwide)

Specification for a 2-quart crock:
Height: 8 1/2 inches
Diameter: 7 inches
Weight:

Extra large water reservoir (spend less time keeping it filled).
Water moat includes a pour spout (makes it easier to remove water from the moat).
Weights completely glazed (easier to keep clean and mold free).
224 reviews!

Sarah Kersten

Modeled after a traditional Chinese design, these crocks are designed by Sarah Kersten and hand crafted at her studio in Berkeley, California.

Sarah’s work is inspired by her love of beautiful, functional ceramics, and her desire to produce heirloom-quality fermentation crocks.

Crocks come with glazed porcelain weights and a letter-pressed booklet of recipes and instructions.

Sizes: 2 quart (2 liters) and 6 quarts (5.7 liters) capacity
Glaze: Non-toxic
Made In: USA, California

Specification for a 6-quart (5.7 liters) crock:
Height: 10.5 inches
Diameter:
Weight:

Live in Canada?

There is only one company in Canada that carries water-sealed fermentation crocks.

Bio Supply

Bio Supply carries the Schmitt & Sohn fermentation crock in a variety of sizes. With typical German ingenuity, these crocks are created with a modern twist using a natural clay slurry which reduces the weight while increasing the durability.

Bio Supply will ship across Canada. Contact them for shipping costs. Their store, House of Nutrition, is located just outside of Victoria, so if you live on Vancouver Island you can pick one up at their store and save on shipping.

If you live in the Cowichan Valley – as I do – you can buy one at The Community Farm Store.

Live in Australia or New Zealand?

I’ve come across a few websites that cater to fermenters living outside the United States. Please share in the Comments Section other companies you’re aware of that I haven’t come across yet and I’ll add them to the list. Thanks.

Scythes Australia

Scythes Australia is located in Mudgee, NSW. They import fermentation crocks from Zaklady Ceramiczne that are made at a factory in Poland.

Scythes Australia carry the 5, 10 and 20-liter water-sealed crocks complete with weights and a set of fermentation recipes. I think these crocks are made by the same company making the Boleslaweic crocks shown at the beginning of this section.

Mad Millie

Just the color makes me want to buy one of these.

The Mad Millie crock is a 3-liter comes that is shipped with 2 traditional clay weights, instructions and recipes.

European Based Companies

Ken Bours Ceramics Agency

Ken Bours Ceramics Agency is located in Nederland and ships worldwide.

They carry a variety of water-sealed fermentation crocks in sizes from 2-liters to 25-liters. Style vary all the way from the traditional straight-walled to hand-etched rounded. Some are handmade by master Dutch Ceramist Daniel Lebon.

WHEN to Ferment in a Crock

Image by Shelly

Practical

Just about any time that works for you with all that you are juggling in your life.

When I bought my first crock – a 10-liter Harsch Crock – I made a batch once a month. Just when my family was about to finish our last jar of Dilly-Delight Sauerkraut (The only flavor I made at that time.), the next batch was ready to harvest.

So, on my next shopping trip into town I would purchase 4 or 5 heads of cabbage and get to slicing. With this approach, I was fermenting throughout the year and able to notice changes in the sauerkraut depending upon the temperature I was fermenting at.

Ideal

Fall, when cabbages are plentiful at the markets – at least in North America – and there has been a few frosty nights to sweeten the cabbage is a great time to make sauerkraut.

Now that I have not only great local sources for cabbage in the fall, but an extra refrigerator to store a year’s supply of sauerkraut, I make the bulk of my sauerkraut seasonally. Nothing beats a fully-stocked refrigerator.

Avoid

Hot summer when higher temperatures fall outside the ideal range.

If temperatures are on the warm side, ferment for a shorter time period, 2 to 3 weeks instead of 4 to 6 weeks.

HOW to Ferment in a Crock

I have published the How to Make Sauerkraut In a Crock in 7 Simple Steps [Healthy, Flavorful, Easy] recipe where I go into greater detail and include many pictures on how to make sauerkraut in a crock.

5 Pounds Cabbage & Vegetables – 3 Tablespoons Salt

This quick overview is here just for a summary. See How to Make Sauerkraut In a Crock in 7 Simple Steps [Healthy, Flavorful, Easy] for the full recipe, but for now here are a few points to keep in mind:

Make sure you have successfully made a few jars of How to Make Sauerkraut In a Jar in 7 Simple Steps [Healthy, Flavorful, Easy]. This recipe teaches the basics for you to be successful when fermenting a large batch.
Make successive 5-pound triple batches. A triple batch would call for 3 times the ingredients listed in my recipes. This quantity just fits into an extra-large mixing bowl.
Use 3 tablespoons of salt for each 5-pound batch.
Pack tightly into your crock, repeating with successive 5-pound batches. Stop 4 to 6 inches from the crock opening. Pack any excess in quart (liter) jars.
Place weights in, pressing down firmly to get the brine to rise above the weights.
Put the lid on, fill the trough with water and enjoy the music that will ensue in a couple of days. Monitor the trough, making sure it is kept full of water. This is your anaerobic seal.
Find a home for your crock, where it can ferment undisturbed for 4-8 weeks at 65-72 degrees Fahrenheit. To protect your floor from condensation, raise the crock off the floor with a few blocks of wood. The bottom of most crocks is not glazed and moisture does transpire through to the floor.
Ferment for a longer time if temperatures are cooler; shorter time if temperatures are warmer.
When fermented to your liking, pack in quart (liter) jars and store in your refrigerator.
When done with the fermenting, store the weights in an open-air environment, or let thoroughly dry. I used to store my weights in the crock where traces of moisture still in the stone resulted in moldy stones. No fun.

HOW to Care for Your Crock

Luckily, these crocks are pretty much carefree. There are a few things to be aware of, however.

Smoothing Out the Edges

Inspect your crock when it arrives. If you notice some rough edges, here’s a tip left by a potter in one of the comments sections:

The unglazed edges on the various crocks and lids are often rough enough to scratch a counter. Before using your crock, simply get wet-dry sandpaper (the black stuff) and do 20 seconds with 180, 200 and 220 grit and then 20 seconds with 400 grit under running water and those edges with be super smooth.

Avoid Ruining Your Floors

The bottoms of most crocks are not glazed and moisture can transpire through to the floor. When fermenting with your crock, make sure you protect your floor from condensation. Raise the crock off the floor with a few blocks of wood.

Removing Mold from Your Weights

According to Mark Campbell of Mark Campbell Ceramics, as discussed in this podcast, mold can’t be removed with bleach. He believes all the bleach does is dye the color of the mold; it does not completely remove the mold.

Instead, he recommends cleaning the crock and weights with some vinegar and then washing them well with soapy water. Next, put the weights (not the crock) inside a cold oven and then turn the oven on to 250 degrees and let them sit in there for 30 minutes. Turn the oven off and wait for the weights to cool down so that you can remove them with your bare hands.

The heat and the vinegar will kill the mold. Mold is more of an issue with unglazed weights. With glazed weights, it is much easier to just rinse off the mold.

Storing Your Crock and Weights

Early on, I stored my unglazed weights in my crock. Bad idea! The next time I opened my crock, I was greeted by mold-encrusted weights.

Weights need to dry in open air for a good week to make sure there is no longer any moisture left in them. I do this and then store them by themselves in one of my kitchen cabinets.

Which Fermentation Crock are You Lusting After? Know of a Company I Need to Add to the List?

Please share in the Comments Section. Thank YOU!

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