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Guide to Choosing a Fermenting Crock

Hadar Iron

Ceramic Artist & Fermentation Educator

Following the revival of the fermentation wave in the US and worldwide in the past 20 years and supported by scientific findings of the microbiome effect on our physical and mental health, a tool for home-made fermented foods is a staple in the kitchen. On this page, I want to help you find the best tool and share my experience of making tasty probiotics with endless flavors.

I started making ceramic fermenting crocks because I love beautiful, functional kitchenware and tableware. As I had had a few of my vessels handy in my kitchen, I then fell in love with the fermentation idea and process of making. To my surprise, a few months after eating fermented foods regularly, I inherently found myself on a healing path, which then led to departing from medication and developing a self-sustained healthier body.

This is why I believe a fermentation crock is a must tool in every household.

What is a Fermenting Crock

A fermenting crock is usually referred to as a ceramic vessel, but there are other containers and methods in which fermentation can be done, such as plastic buckets, plastic vacuum bags, or glass jars. I make Water Sealed Fermenting Crocks, which to many chefs and me, creates the best sauerkraut, kimchi, and pickles. But first, let me tell you a little bit about the different methods and containers for fermenting.

Types of Fermenting Crocks

  1. Open
  2. Water sealed
  3. Plastic buckets
  4. Glass jars
  5. Vacuum plastic bags

Open Crock

It is a ceramic cylindrical container, which is sold with or without a lid. Although It is easy to clean with its vertical walls and costs less than the water-seal, there are several disadvantages: the stone weights are not sold with the vessel, and there is a need to put a plate on top to press all the vegetables down below the brine. Since it is open, the vegetables are susceptible to develop mold from exposure to air. And last, the pungent smell produced during the fermentation has a free path into the room. Therefore these crocks are usually placed in the basement or any other space that is not part of the dwelling.

Water Seal Crock 

It is a ceramic vessel with a rim shaped like a trough for placing the lid inside. After placing the lid, water is added to the trough and fill in the space around the lid’s wall. The water creates a perfect sealant to prevent oxygen from entering the Crock’s interior space and a barrier material that absorbs the smell. The water-seal Crock is usually sold with a pair of stone-weights and a lid. It costs more than the open Crock but is easier to use and much more efficient in keeping the vegetable safe from bugs, insects and mold. While the Crock is closed and sealed yet, gases produced during the decomposing can escape through the water.

Plastic Buckets 

It works the same as an open ceramic crock, though you can get them in bigger volumes and cheaper. Make sure, though, to get a food-safe grade plastic bucket. To ferment in a bucket, you will need to add a plate on top of the vegetables and weights. Also, a towel on top of the bucket is recommended to keep bugs and insects away. Overall, the process is open and doesn’t guarantee success while storing food in plastic for days or weeks.

Glass Jars

The jars work similarly to the open Crock too. However, the jars are versatile in volume, and I see an advantage to have a few small jars for fermenting sauces, such as chilies hot sauce, which is made in a small amount of a pint or a quart size jar. Weights need to be provided to fit the jar, and some packages have glass weight included. The jar can be used with an Airlock cap system to allow the gasses to escape; they come in different sizes, from a cup to a gallon jar. However, using an airlock cup introduces plastic and silicon into food production.

Vacuum Plastic Bags

Food-safe plastic bags usually come in rolls and several sizes, from a pint to several gallons. The bag needs to be sealed by a hot sealing machine to seal the bag in a vacuum condition, such as FOODSAVER® VACUUM SEALERS

These both are not cheap nor sustainable, or environmentally friendly.

How Do You Use a Fermentation Crock?

There are three key elements in using a water seal crock: Compressing, Submerging and Sealing, all of which are related to avoid oxygen and let the lactobacillus bacteria work in its anaerobic environment peacefully without the interference of harmful bacteria and mold. For a complete guide, see how to use a fermenting crock.

4 Tips for Shopping for a Fermenting Crock

  1. Avoid Plastic – The material you use in fermenting makes a big difference. Ceramic is the best material for a fermenting vessel. Avoid crocks made of plastic. Plastic crocks can trap bacteria and the smooth texture is not optimal for fermenting
  2. Made with Safe Materials – Research and choose a ceramic crock made with non-porous clay and glazed with non-toxic materials. See safe non-toxic materials and glazes used in our studio in Guide to High Fire Ceramics.
  3. Includes Stone Weights – Make sure the crock you buy includes stone weights. These are critical to the fermenting process. They should be made of a similar material to the crock itself. Ceramic is best.
  4. Inner Wall Height – Ceramic fermenting crocks have a water-trough with two walls: the outer wall and the inner wall. Make sure that the inner wall is taller than the outer wall. Some crocks have a shorter inner wall because it makes the glazing process significantly easier. This may seem like a small detail, but it makes a big difference in the fermenting process. When the inner wall is shorter, dirty water can overflow into the outer wall cavity from the trough and ruin the process. Before you buy a crock online, make sure there’s a product image showing the inside of the crock with the lid off.

Why Use a Fermenting Crock

The water-seal fermenting Crock is the best method to make fermented foods enjoyable, efficient, reliable and sustainable. After you sealed the Crock you can relax knowing that the crock-mechanism will provide essential nutrients and probiotics for you and your loved ones. At this point, the ceramic Crock becomes a featured element in the house when you want to look at it every day and be inspired by its work and beauty. High fire ceramic crock from my studio is what you would like to watch working on your kitchen counter as a piece of functional art.


Where to buy a fermenting crock?

You can buy water seal ceramic crocks on my website’s shop or on my Etsy shop. If you are in the Seattle area, you can also schedule an appointment at my studio to browse and purchase crocks in person.

How to clean a fermenting crock?

Washing with soap and water the interior of the Crock after using it is recommended. If there is an undesirable small from the last fermentation, you wish to get rid of before the next batch, fill the Crock with water and baking soda and leave it overnight. DO NOT wash the Crock with vinegar since the vinegar deposit may harm the next batch’s lactobacillus bacteria. For a more thourough explaination, see our guide to cleaning a fermenting crock.

What size fermenting crock do I need?

I recommend a one-gallon fermenting crock that is easy to manage and sufficient for a family of 2-5 people. 2-3 cabbages all together 6-8 Lb. can be packed into a one-gallon crock; you would be amazed how much the cabbage shrinks after mixing it with salt. If you and your family eat fermented food regularly and have a cycle of two weeks fermenting in the crock, one-gallon will provide enough. If you wish to work with a bigger crock, get the 1.5 gallon or the 2 gallons. If you are a beginner fermenter and want to try making fermented foods in a small amount, I have a 1/2 gallon for you. 1/2 gallon is also good for condiments, such as dry chili pepper hot sauce and tomato paste.