The salt starts the cabbage in the leaching process. I don't know if it creates enough liquid to cover the whole batch.
I make a brine using 3 Tablespoons of salt to 2 quarts of water. I pour over the cabbage till just barely covered. I think that there is well over an inch of liquid now.
If the cabbage does not stay below the water line, it apparently spoils. This is the second time making it. I read lots of articles from local university extension services. Lots of recipes, and watched a bunch of You-Tube videos.
You don't need a crock. An old 1 gallon glass jar will work. The also sell kits on the Internet for the glass bottles. The kit's allow the gases to burp or escape.
Once you've mad a batch, you'll never go back to canned kraut again.
As for hot baths and pressure canning, I don't process mine. I use sterilized jars, and once fermented, I place in pint or quart bottles and place in an old refrigerator. It stays "crisp" this way.
