Fermenting Crocks Compared; Open Crocks vs Water Sealing Crocks

What is fermenting?

First, before we dive into discussing the crocks let’s discuss what fermenting is. Fermenting is an ancient food preservation technique that has been popular in my family my entire life. Recently home fermentation has experienced a widespread resurgence in popularity, in part due to the many health benefits of fermented foods and the popularity of fermenting experts on YouTube sharing their experiences and expertise.

Fermenting is easy. Fermented foods have good bacteria to help break down complex carbohydrates that you eat. This fermenting and metabolizing process results in other substances that are beneficial to your body, too.

Some of the most commonly fermented products/foods to make are sauerkraut, kimchi, pickles, olives, and hot sauce. You can ferment just about every fruit or vegetable.

Lacto-fermentation requires nothing more than fresh produce, salt, and water because it relies on sugars and bacteria naturally present in these foods. While the process is simple, it helps to have the right tools. That’s where open and water sealing crocks come into play.

Fermenting Crocks

The most traditional type of container used for fermenting is a ceramic crock, and there are two main types of ceramic fermenting crocks available: open crocks and water sealing crocks. Each type has its pluses and minuses, let’s talk about each below.

Image from Ohio Stoneware Website

Open Crocks

Open crocks are simple, straight-walled vessels sold with or without a lid and weights. In the most basic setup, an open crock can simply be covered with a cloth, with ordinary items like plates or stones used as weights, or you can purchase weights and a lid separately. I personally prefer to have the weights and lid rather than just using a cheesecloth.

You want to make sure your crock has a lead-free glaze. This is important to confirm if you purchase your crock from a non-USA-based maker of crocks including custom-made crocks. If the glaze is lead-based there is the potential of lead leaching into your ferment.

Open crocks are usually less expensive than water-sealed crocks and their wide, cylindrical shapes make it easy to fit a variety of larger batches and whole vegetables. The straight cylinder shape provides the largest easy-to-accesses surface area. Weights and lids often need to be purchased separately and can dramatically raise the cost of an open crock. If you don’t have the weights you need to create a makeshift weight with a plate or something heavy and I don’t like to do that as in my experience it has increased the risk of contaminating your ferment.

Open crocks that are not covered with a fitted lid or properly submerged under the brine have the potential to develop a layer of yeast which is harmless but can appear when a ferment is exposed to the air. There’s also the possibility of fruit flies or other insects or their eggs getting into or laying in your ferment.

Depending on their size, open crocks are quite easy to clean, since their bases and openings are the same diameters. Because these crocks are stoneware you do not have to use soap, in fact, YOU SHOULD NOT USE SOAP ON THE UNGLAZED WEIGHTS. If you do, the unglazed weights could absorb the soap and taint the flavor of your food. It could ruin your ferment.

A large open crock is ideal for me as I can easily make large batches with it.

The benefit of an open crock is so that the pressure won’t build up. The contents are also easy to get to so you can smell, see, taste, and learn as the ferment matures. The con of an open crock is that access to oxygen enables aerobic (formed-in-oxygen-environments) yeasts and molds to develop on the ferment’s surface.

Fun Fact: The crock-producing capital of the United States of America is known to be Roseville, Ohio.

Image from Roots and Harvest Website

Water Sealing Crocks

The lid of water-sealed crocks sits in a shallow “moat” around the mouth of the crock. A water-sealed fermentation crock or a sauerkraut crock is a stoneware pot that is used to prepare fermented food. It holds vegetables in a brine solution and comes with a sealed top. The difference between a sealed crock to an open one is a moat around the opening where the lid fits on and creates a seal.

A water sealing fermenting crock is a German crock design with a lip around the opening mouth designed to prevent any outside air from getting in and semi-circle weights for keeping the vegetables submerged. This is a very efficient method for preventing a variety of complications with your ferment. The disadvantage to the water sealing design is that it’s only effective if you leave the crock sealed. If you want to look at, feel or smell your food the fundamental purpose of the design is defeated.

The water in the moat allows the CO2 gasses that build up in the crock through the fermentation process to escape, but no air to come in. It essentially works like an airlock. This airlock prevents yeasts and mold from entering and developing on the surface of your ferment. It is said by some that the end product is tastier and of higher quality than when using an open pot.

The opening of the water sealing crocks is smaller and you have to angle the weights to get them in and out. This reduces the amount of produce you can put into each fermenting batch. You can’t fill the crock more than 4/5 of the way full. In my personal opinion, this is the number one con. I like to make big batches. Also, because the opening of the water sealing crock is smaller you can’t just use any old plate or bowl as a weight. You really need to invest in the proper weights that fit exactly.

Just like the open crocks, the water sealing crocks are stoneware. The water sealing crocks have an interior ridge where the main crock and groove come together. The risk with this groove is that if you don’t clean it well enough you risk mold. Because these crocks are stoneware you do not have to use soap, in fact, YOU SHOULD NOT USE SOAP ON THE UNGLAZED WEIGHTS. If you do, the unglazed weights could absorb the soap and taint the flavor of your food. It could ruin your ferment. One of the best ways to clean it is with warm/hot water and a sturdy brush.