If you made your first Sauerkraut, you probably experienced it: You follow your recipes as close as you can, weighed down the kraut, and covered the jar with a cloth. The waiting game has begun. You check up on your jar 24 hours later only to find the sauerkraut brine disappeared! The recipe stressed how important it is to keep the kraut submerged, right?
If you lost some brine during fermentation, just add a little more brine, containing a cup of (preferably distilled) water, a pinch of salt, and a few drops of lemon juice or vinegar. Be generous with the amounts as you can never have too much brine really.
Where did all the brine go?
There are two physical reactions, that make it seem like you’re losing brine by the hour.
1. Sauerkraut brine evaporation
Unlike kimchi or other pickled fermented foods, we don’t seal off our sauerkraut jar. Instead, we only cover the top with a cloth to ensure adequate airflow. However, this airflow also allows the sauerkraut brine to literally disappear into thin air! The evaporation process is amplified if you’re making sauerkraut in an arid, hot environment.
2. Fermented cabbage sucks up water
Remember when you first salted the cabbage to draw out the water? Now as fermentation progresses, the cabbage wants to have this water back. It tends to swell up like a sponge and absorbs some of the surrounding water. Again no big deal. This is perfectly natural and desirable.
Ultimately though, sauerkraut that isn’t submerged is not ideal. So let’s fix that!
Fixing sauerkraut that’s lacking brine
Before you go nuts, make sure your sauerkraut is actually lacking brine. There is a good chance, you didn’t weigh it down strong enough. Push down the kraut as hard as you can to check for air pockets. If the kraut is suddenly fully submerged again, simply add more weight to the top to keep it that way!
If there’s still not enough brine, we have to add some more brine.
How do you make extra brine for fermenting sauerkraut?
When adding additional brine into our sauerkraut our goal is to increase the volume without changing anything else. Therefore we need to keep the pH (Sauerkraut’s pH can be as low as 3!)and salt content around the same. We suggest adding a brine that contains the following ratio of ingredients:
- Cup of distilled water
- A shot of lemon juice
- If you don’t have fresh lemon juice at hand, simply use vinegar, lime juice, or citric acid instead.
- 1 teaspoon of salt
- A bit of salt is crucial: If we pour normal freshwater on top of the sauerkraut, we are creating an environment, where other bacteria, fungi, and yeasts can thrive. This is less than desirable for obvious reasons!
Add as much as you like, but keep the ratio the same.
The role of brine in your sauerkraut
- When your sauerkraut gets submerged in the brine, an anaerobic environment is created.
- These anaerobic conditions lay the groundwork for the fermentation process.
- The bacteria will begin to spread in our jar and eat all carbohydrates (sugars).
- This will be metabolized into ethanol, CO2, and, most importantly, lactic acid.
In a nutshell: Brine is a convenient tool to control the fermentation of our sauerkraut.
Made a little too much brine? Don’t throw it!
The juice from your sauerkraut is a valuable asset to all your fermentation endeavors! Store it in a mason jar in your fridge and use it as a probiotic started for the future. This will greatly speed up the proliferation of bacteria and thus increase the rate of fermentation.