How To Make Homemade Sauerkraut in a Mason Jar

Raw Fermented Sauerkraut- When life gives you cabbage, you make sauerkraut — and homemade sauerkraut is a world apart from the stuff that comes from the grocery store. It’s crunchy and delightfully sour, perfect for topping a round of beer-braised brats or layering into a big sandwich. Don’t worry about needing a special crock or making so much you’ll be eating it for months.

Today I’m showing you how to make a small batch of sauerkraut in a mason jar — it’s just enough kraut to get you hooked!

Sauerkraut is often one of the first fermentation projects recommended to curious DIY-ers, and with good reason: It’s beyond easy to make, it requires very little special equipment, and the results are dependably delicious. All you need to do is combine shredded cabbage with some salt and pack it into a container — a crock if you have one and want to make a lot of sauerkraut, but a mason jar will do just fine for small batches. The cabbage releases liquid, creating its own brining solution. Submerged in this liquid for a period of several days or weeks, the cabbage slowly ferments into the crunchy, sour condiment we know and love as sauerkraut.

How Is Sauerkraut Fermented?

Sauerkraut is made by a process called lacto-fermentation. To put it (fairly) simply: There is beneficial bacteria present on the surface of the cabbage and, in fact, all fruits and vegetables. Lactobacillus is one of those bacteria, which is the same bacteria found in yogurt and many other cultured products. When submerged in a brine, the bacteria begin to convert sugars in the cabbage into lactic acid; this is a natural preservative that inhibits the growth of harmful bacteria.

Why Should Sauerkraut Be Fermented?

Lacto-fermentation has been used for centuries to preserve seasonal vegetables beyond their standard shelf-life. The fermentation process itself is very reliable and safe, and the fermented sauerkraut can be kept at cellar temperature (around 55°F) for months, although those of us without cellars can make do with storing the kraut in our fridges. Besides preserving the cabbage, this fermentation process also transforms it into something incredibly tasty and gives it additional health benefits — fermented sauerkraut contains a lot of the same healthy probiotics as a bowl of yogurt.

What Do I Need to Make Sauerkraut?

At the most basic, all you need is cabbage, salt, and some sort of container to store it while it’s fermenting. It’s important that the cabbage remain submerged in its liquid during fermentation. When making sauerkraut in a crock, you usually place a weighted plate over the cabbage to pack it down and keep it submerged. When fermenting in a mason jar, inserting a smaller jelly jar filled with rocks or marbles in the mouth of the larger jar serves the same purpose.

The cabbage near the surface tends to float, so when fermenting in a mason jar, you need to either tamp down the cabbage a few times a day or place a large outer leaf of cabbage over the surface of the shredded cabbage to hold it down. Also be sure to keep the jar covered at all times with a clean cloth or piece of cheese cloth. This will allow airflow, but prevent dust or insects from getting into the sauerkraut.

How Long Does It Take to Make Sauerkraut?

For a small quart-sized batch like we’re making today, the minimum time is about three days, although the kraut will continue to ferment and become tastier for many days after that. As simple as it sounds, the best rule of thumb is to keep tasting the kraut and refrigerate (or take it cellar temperature) when it tastes good to you. The sauerkraut is safe to eat at every stage of the process, so there is no real minimum or maximum fermentation time.

What Can Go Wrong?

Not much! You may see bubbles, foam, or white scum on the surface of the sauerkraut, but these are all signs of normal, healthy fermentation. The white scum can be skimmed off as you see it or before refrigerating the sauerkraut. If you get a very active fermentation or if your mason jar is very full, the brine can sometimes bubble up over the top of the jar. This is part of the reason why I recommend using a larger mason jar than is really necessary to hold the cabbage. If you do get a bubble-up, it’s nothing to worry about — just place a plate below the jar to catch the drips and make sure the cabbage continues to be covered by the brine.

It is possible you might find mold growing on the surface of the sauerkraut, but don’t panic! Mold typically forms only when the cabbage isn’t fully submerged or if it’s too hot in your kitchen. The sauerkraut is still fine (it’s still preserved by the lactic acid) — you can scoop off the mold and proceed with fermentation. This said it’s still important to use your best judgment when fermenting. If something smells or tastes moldy or unappetizing, trust your senses and toss the batch.

If you are interested in bio fermented sauerkraut, check our website to learn more about organic fermented sauerkraut