Why I Stopped Fermenting Sauerkraut In Mason Jars

Hola! Thanks for stopping by, it is 'muchly' appreciated! I wanted to give you some feedback on my personal experience using mason jars for fermenting, and why I moved away from them as my go-to choice. It's not that they are a bad choice, or don't do a pretty good job. No, they work just fine, but I got to a stage in my 'fermenting journey' that I just felt that I outgrew them and needed to take a step up.

Now, before the haters descend, I want to say that this is MY personal experience, you may completely disagree. Or you may be making your own sauerkraut or kimchi in mason or other glass jars, and finding it all a bit of a fiddle.

OR...you may have never fermented a vegetable in your life, and just be starting out, wondering what is the best fermentation vessel to choose.

This post is to let you know about the frustrations and obstacles I experienced fermenting sauerkraut in mason jars, and I hope that it can provide you with some ideas on how you might want to look at your process, whether an existing one or one you are just starting.

But at the end of the day, just starting is vital. Use what you have or can afford. If jars are it, cool, once you have a handle on things you might want to upgrade...perhaps.

I started my journey into fermented vegetables in 2013, when I started experimenting with sauerkraut. I've alway been something of a tightwad, and the idea of spending £40 ($70) on a water sealed fermentation crock gave me goosebumps. I am always looking for ways to repurpose existing equipment or doing something on the cheap. Maybe it is just the homesteading and self reliance mentality, not sure.

So, I managed to pick up quite a few wide mouth mason-style jars from thrift shops, from local Facebook pages where people advertise their stuff. Over here in the UK we have 'Kilner jars'  (aka Fido Jars in the USA) with flip up lids that are excellent for storing pickles and fermented vegetables in.

I did a lot of research, picked up some books and watched some video and got really excited about fermenting. Still am actually!

Now, the thing with fermenting is that the environment in which we place the vegetables needs to be anaerobic, so without oxygen being able to reach our shredded cabbage or other veg. We make sure that the vegetables are kept submerged under a brine solution, and ideally exclude as much air as we can from the jar.

Although not essential, the best way to keep the vegetables submerged is to weight them down using specially made weights. This is what you get included in water-sealed German-style crocks, which makes the whole process a lot easier and more convenient. You can actually buy weights that you can use in mason and other jars, OR you can use an improvised method, I'll show you a couple in a moment.

Anyhoo, back to the story. Where was I?

Oh yes, here are my reasons for moving away from using these as fermentation jars for sauerkraut and other vegetables, and now use a proper crock for all my ferments:

Reason #1 - Mason Jars Are A Pain For Bulk Filling En Masse

This may seem like a minor point but when you've finely sliced 3 heads of cabbage, salted it, left it to wilt and then want to pack it tightly into jars, having a sh*t ton of jars to fill becomes a real pain. Wide-mouth jars make the experience a little less miserable, but it's still awkward to get all that cabbage into a jar, pack it down, cover it with brine, and move onto the next one.

Sure, if you get some really large jars and focus on just doing small amounts at a time it works, but as a person with large hands, I really can't even use my hands to get the cabbage into the jar, let alone compress it. I have to use a cabbage pounder LINK for that.

So imagine, you've filled 5 large mason jars with your raw cabbage or other vegetables. You've topped them up with brine to cover the veg. Now, you've got to find a satisfactory method to weight the cabbage down below the surface, keeping air from getting to it.

This is my next big gripe that pushed me in the direction of a proper sauerkraut crock.

Reason # 2 - Weighting 'Stones' And Mason Jars

You'll see that I put 'stones' in brackets in the title of this section. In German style crocks a pair of weighting stones is included, and these are placed on the surface of the cabbage to hold it down below the surface of the brine.

These crocks also have a really handy water gutter in which the lid sits to prevent air entering the crock, but allowing built up carbon dioxide to escape. Check out what I mean here, on my crock at home.

Water in gutter of crock
Sauerkraut crock with lid in place

You end up with a pressurised environment inside the crock with no oxygen at all, perfect for excellent fermentation to take place.

With mason or fido jars, or any other jar or open vessel, you need to find a way to replicate that environment, at least the weights to weigh down the vegetables. Many people use different ideas, some folks don't use anything. Here are a couple of options that can work fine, but they are just a bit less effective than a crock with a water seal.

1. Buy fermenting weight stones that you can place in your jar.

Many companies are now making fermenting weights like these two on Amazon to allow jar and open crock users to effectively weigh down their ferments.

These are a great idea and you should definitely consider using them if jars are your chosen vessel. You'll find it much easier and less time consuming, but if you are doing a few jars at a time, you'll need to purchase a few sets of stones, which all adds up in cost.

There are alternatives though...

2. Using jam jars as mason jar fermenting weights.

This is a good idea if you have some that fit inside the neck of your mason jar. Simply fill the jam jar with water, screw the lid on tight, and place it inside the neck of your fermenting jar. Simple!

Of course, this does prevent you being able to use the screw or flip lid on your mason jar, but this isn't a deal-breaker. As long as the vegetables are below the surface, you can cover the jar with a plastic bag and use an elastic band to secure it OR cover with a tea towel, anything to keep the dust and bugs out.

Jam jar as a diy fermenting weight

3. Place a river stone in a plastic bag and use as a weight.

 This is simple and cheap. Obviously it is harder to find a relatively round stone with one relatively flat side that will fit inside the neck of the jar, but it's definitely an option. On the subject of using plastic bags, here is a strategy I used when I was getting started.

4. Use a water filled plastic bag as a fermenting weight.

There are a couple of ways to do this:

  • Place the bottom of the bag into the jar on top of the vegetables, add water and then seal the bag with a sandwich bag tie or similar. Then place the lid on the fermenting jar and seal, ideally loosely so that gas is able to escape.
Water sealed bag as weight for a mason jar
Using a plastic bag as a fermenting weight in a mason jar
  • Place the bottom of the bag into the fermentation jar as before, but use a rubber band to hold the open neck of the bag tightly around the neck of the jar. This method does away with the need for a lid and makes it easy to add water if the need arises.
Elastic band around the neck of a mason jar for fermenting
Fermenting sauerkraut in a mason jar

The problem with any of the above practical methods, other than using NO weight and just sealing your mason jars up is this: It become a slight pain in the a** to check on the progress of your ferment. I like to taste test mine every few days, checking for the appropriate tang and sourness. Using your visual and taste senses is a really important skill to acquire when fermenting food.

5. Use Mason Jar Airlock Lids For Fermenting

Of course, if you have 10 jars you only need to taste test one of them, so it’s not an obstacle that can’t be overcome.

There are quite a lot of options here, that basically allow gas to escape but not let air enter the jar. They don’t overcome the issue if keeping your vegetables under the surface of the brine, but do help with keeping the conditions inside the jar as anaerobic as possible.

Both of these can be picked up on Amazon, but there are plenty of other choices of fermenting lids for mason jars that work quite well.

Pros Of Fermenting Vegetables In Mason Jars

Ok, ok, it sounds like I am really down on mason jars, but there are positives to them. The one that really stands out to me is this:

You don’t need to transfer your fermented veggies into a different storage jar once fermentation is over. You can just seal those mason jars down and stick them in a cool place. Nice!

BUT, if you want to create a lot of sauerkraut or kimchi or [insert ferment of your choosing], you will need A LOT of jars. Some for storage, some for fermentation in process. And with a half decent sized mason jar costing a good few bucks, you would end up spending as much, if not more on jars than you would by just taking the plunge and buying the best fermentation crock you can afford.

Starting in the $60 price range for a 5 liter crock, this is only 5 or so 1 gallon mason jars. And some of those may be for storage, so you might only have a couple for your actual fermentation process.

As well as some of the issues I mentioned above with regard to weighting down, tasting, big hands into small jar necks etc, it is the apparent money-saving benefits of mason jars that really doesn’t prove to be true when you start to consider the requirements.

Once I bought my water-sealed crock everything was a breeze. I could use any jars I could get my hands on for the storage, and ferment 3-4 heads of cabbage in a single crock. The water seal and design ensure that you never end up with moldy or spoiled kraut, and the thickness of the ceramic crock walls helps to keep the temperature much more even.

So, I’m not saying that fermenting vegetables in mason jars is a fool’s game, nothing like it. But if you are really excited about the journey and want to maximise your results while minimizing the hassle, a crock is a great place to start. Also makes an awesome present 🙂

Recommended Fermenting Accessories

Here are a few cool things that you might want to consider if you decide to start fermenting. I love my cabbage pounder and also have a shredder similar to the one below. I've used a knife for a long time, but the shredder speeds the process.

Himalayan salt is the best in my view, check out my article on the best type of salt for fermenting if you'd like to learn more.

2 thoughts on “Why I Stopped Fermenting Sauerkraut In Mason Jars”

  1. I have a crock you show in your pictures, but larger size. There are some negatives about it too – harder to fit to wash in a sink, and stones are too porous for my liking. I can’t wash them properly out. I will try soaking them in vinegar water like you recommend. And by the way, I agree about not using food processor for cutting – I got frustrated also with constantly stopping it, opening, etc.
    I want to try making kimchi in small amount first to see, how I like it, so I will use quart (liter) jar and use jelly jar as my weight.

    • Hi Daiva

      Sure, everything has it’s benefits and limitations, even a crock 🙂 Yes, I know they can be a little tricky to wash up in the sink. On the porous stones, I ALWAYS soak them in a water/vinegar solution, keeps bacteria from getting in and also, if they are soaked already, they won’t take up any of your precious brine.

      And although I don’t love mason jars for fermenting, small scale experiments are good. I’ve kinda got my kraut and kimchi sorted now so I prefer to do a larger batch.

      Good luck with your kimchi making


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