Cut the head of cabbage in half and then remove the inner core. You don't want this in your sauerkraut, it is too tough to eat.
Slice the cabbage into thin slices and place into a bowl. Sprinkle the salt over the cabbage and toss to combine. Let this sit for around 15 minutes or more. The salt will help to soften and draw out the natural liquid in the cabbage.
After 15 minutes the cabbage should have started to release some of its water. Massage the cabbage with your hands for about 10 minutes to help it soften and release even more of its water.
Pack your cabbage into a clean mason jar as tightly as you can. I use the back of a wooden spoon to compress the cabbage down and remove as much of the air as possible. Once all of your cabbage is packed into the jar, pour whatever remaining liquid was left in the bowl over the cabbage.
Using one of the clean leaves you had set aside earlier, rip it to fit the jar and push it down into the opening so it covers the cabbage and helps to keep everything submerged under the liquid. See notes for Brine recipe if there isnt enough liquid.
Place a fermentation weight over top and cover loosely with a lid or a cloth. Make sure to write the date on your jar, and store the sauerkraut in a cool dry place that is not directly affected by sunlight
Timing: This is going to vary house by house and person by person. Start with letting it ferment for 1 week and give it a taste. It can take between 1 and 3 weeks to get the tang you are looking for in your sauerkraut. Once you have achieved desired tanginess, cover with an airtight lid and store in the fridge for up to 6 months