The crock is about 3-gallon size, plenty of room for the 10 pounds of cabbage I had in mind for a new batch of sauerkraut. The process is remarkably easy and results in a freshly fermented kraut that you can eat very simply as is, or as the basis for an elaborate choucroute. There is little resemblance between freshly fermented kraut and the processed stuff that comes out of a can. Some people swear by the brine as a health tonic, since it is swarming with beneficial bacteria, just like yogurt.
The formula is as follows: cut a full head of cabbage into quarters and trim away the outer leaves and the tough core (toss these in the compost pile). Shred the cabbage as you would for a cole slaw. I just slice it up with a serrated bread knife. For every five pounds of shredded cabbage, toss with 3 tablespoons pickling salt or fine sea salt--you must use a salt free of iodine or chemical additives.
Place the salted cabbage in a heavy-duty plastic bucket or ceramic crock. With your balled-up fist, press the cabbage down as tightly as possible. Already the salt will be drawing liquid out of the cabbage. Over the next 24 hours, you'll want the cabbage completely submerged so that it is not exposed to oxygen and any airborne pathogens.
Next day, cover the cabbage with a tightly-fitting ceramic plate or non-resinous piece of wood and press down so that the weight is submerged in the brine. Weigh this down with a heavy object, or a large plastic container filled with water. Cover the whole thing with a tea towel to keep out dust.
What happens next is, a progression of bacteria already present on the cabbage will begin to nosh on the kraut, creating a lactic acid that repels spoiling kinds of microbes. This lacto-fermentation process I find best takes place at a temperature around 68 degrees (Fahrenheit). See if you don't have a dark, quite place in the house where the bacteria can do their work in peace. It will take four to six weeks, typically. Taste the kraut occasionally for doneness, and just scrape away any mold that might form around the edges.
You can now eat the kraut as you like. Storing it in the refrigerator will slow the fermentation process, but the bacteria are still alive until cooked. I still have sauerkraut in the fridge that I made nearly a year ago. Looking into my crystal ball, I see the fuzzy outlines of a choucroute in our near future....