Sauerkraut: learning to do food fermentation

Fermentation is a way to enhance the taste, nutritional value, and shelf-life of food. It is vastly superior to other methods of food preservation, such as canning, which makes the taste bland and removes many nutrients. Indeed food that has been fermented is more nutritive than it was before, because bacteria synthetized complex molecules (ie. b vitamins) and allowed the vegetables' nutritive molecules to be more easily absorbed by the digestive system.

The importance of our gut microbiota (the bacterial communities in our belly) is much more appreciated than it used to be, being one of the most exciting subject in contemporary biology. Indeed an unbalanced gut microbiota may be a significant factor towards the development of several serious physical or mental health problems, such as obesity, inflammatory bowel disease (IBD), diabetes mellitus, metabolic syndrome, atherosclerosis, alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), cirrhosis, and hepatocellular carcinoma (source). The best thing you can do for the health of your gut microbiota is to eat unpasteurized fermented food.

Fun fact: my interest in food fermentation was my main motivation to study biology at university.

One of my favourite fermentation, for its simplicity, versatility and low-cost, is sauerkraut. It has nothing in common with the soggy-winey things called sauerkraut in supermarkets! It's actually crisp, tangy, fresh and flavourful. I've been doing it for almost 10 years, since then there is a jar of sauerkraut to be found in my fridge most of the time.

Also learning the fun and wholesome art of fermentation might be a fine new year's resolution! And it's nice to learn to do the things our ancestors used to do.

Preparing sauerkraut

• Buy a cabbage (or two). I like to mix purple cabbage with green cabbage, it makes a profound pink colour which always adds visual appeal to a dish.

• Cut the cabbage in small layers (as if making coleslaw - the photo above is a bad exemple, I cut grossly). Put in a jar or any pot (not made of metal), enough to fill about three quarter of it.

• Add a generous amount of salt (such as the small sea of sea salt visible in the photo above). It actually won't taste salty after a week, because the bacteria will have uptook the salt into their cells, making it imperceptible for our taste buds. The salt is essential, as it makes the cabbage release its water by osmosis, and it inhibits the growth of foreign bacteria (the useful lactobacilli that do most of the fermentation process are in abundant quantity on the cabbage, so they'll survive the salt, however foreign bacteria invading from the air will not).

• With an appropriate tool or your fist (I use a wooden musical percussion instrument), vigourously crush the cabbage.

• The volume in the container should have dropped muchly. Therefore repeat steps 2 to 5 until the container stays between half-full and three-quarter-full.

• Store it out of strong direct sunlight.

• Every day for about four days, mix and crush the cabbage again (alternatively you can use a weight, such as a flat stone, the idea is simply to keep the cabbage in the water)

• If on the third day you see there still isn't enough water over the cabbage to submerge them (it takes some time for the salt to release it through osmosis), you may add water until it's about 1 cm over the cabbage.

^{It looked like this before I added a small volume of water.}

• When the smell is sauerkraut-like, and there has been noticeable visual changes, put in the fridge for aging at least 4 days. If there's still vigorous fermentation (bubbling is noticeable), keep it out of the fridge for one more day.

• Serve! Goes well with almost anything from any country.

^{https://busy.org/@a0i/rice-of-tranquility-2-with-tofu-apples-kale-and-sauerkraut}

I hope this inspired you, and I'd be glad to answer any questions.
-aoi