Clean and dry your equipment and hands very well before starting.

Remove tough outer leaves and core from cabbage.

Thinly slice cabbage, making the slices as uniform as possible. I use a food processor to make this quicker and easier.

Put the cabbage in a large bowl and mix in the salt. Allow it to sit for a few minutes, and then use clean hands to crush the cabbage until it becomes wilted and starts releasing its juice.

Pack the cabbage into the jar and push it down firmly with your hands. Seal the jar.

Put the jar in an area that is 21-24°C (70-75°F).

Quickly open and close the jar every day for the first few days to prevent pressure from building up.

For the most optimal population of healthy bacteria, allow the jar to sit at room temperature for 3-5 weeks, depending on the temperature of the room. At this point it is ready to eat and should be stored in the fridge. Some people find the sauerkraut has become too sour after a 3 week wait, and prefer only 1 week. You'll have to do some experimenting to see what period of time works best for you.

The sauerkraut should keep for months, stored in the fridge.