Fermenting sauerkraut at home is super easy:
What you need:
1. Crock
2. Weight/plate/brick
3. Cheesecloth
4. Salt
5. Cabbage
6. Water
7. Mason Jars (large mouth)
Chop cabbage and alternately layer it into crock while adding salt to each layer. Bruise each layer of cabbage with a wooden stamper or masher. This will release the moisture from the cabbage into the crock to mix with the salt and create the brine. You are also packing it tightly down into the crock and pushing out air here.
If your cabbage is fresh from the garden, it may have enough water in it to release. If not, add some clean filtered water to the crock until all cabbage is slightly below the water brine level.
Use a fermentation weight to press everything deeper into the crock. If you don't have a disk, a large plate works great with a heavy bowl or brick on top.
Cover with cheesecloth so it can breath, and place crock in a cool dry place like a root cellar or basement and allow to sit for 2-5 weeks. You can check it after 2 weeks to see how it tastes, and simply allow it to ferment longer if you want it stronger.
Lactobacillus bacteria are the key to this process. Lactobacillus occur naturally in vegetables. They are considered harmless and beneficial. Lactobacillus have properties that make them perfect for fermentation: They thrive in an oxygen-free and salty environment; they flourish and ferment where harmful bacteria cannot grow.
Temp around 60-70 degrees works best. Cooler = slower fermenting and crispier, warmer = faster and possibly softer texture.
Once it is fermented simply fill clean wide mouth mason jars, seal tight by hand, and store in the fridge for up to 6 months. No heat canning or pressure cooking needed.
I took these pictures when I was living among the old order Swartzentruber Amish in Ohio. They are of German descent and always have crocks being fermented. Lehman's Hardware in Kidron, Ohio is a massive Amish store that has an entire room filled with handmade crocks and supplies from Germany. Highly recommend if you ever visit the region.
Enjoy.