Halve cabbages through core and slice coarsely off core. (You can slice thinly, if you prefer; just make sure that the slices are the same size, so they ferment evenly.) As you slice, put cabbage in a large bowl, sprinkling and tossing periodically with some salt and spices until you've used all the salt and spices and added all the cabbage. With your hands, crunch and toss seasoned cabbage for about 10 minutes. It will begin to wilt and ooze juices.
Pack cabbage as tightly as possible into a sterilized 1-gal. wide-mouth glass jar, tamping cabbage down hard with a wooden spoon until juices bubble up to just cover the cabbage.
Pour about 3 cups water into a 1-gal. resealable plastic bag (don't seal); then enclose bag in a second bag (still don't seal). Nestle bags onto cabbage, seals up, so that they submerge cabbage and form an airtight layer. Then seal bags. Cover jar with a double layer of cheesecloth or a tea towel and secure with a rubber band around rim.
Store in a dark spot at a temperature between 60° and 75°. Press down on the cabbage every 2 to 3 hours for the rest of the day to encourage it to release more brine.
Check kraut every 2 days, skimming any scum from surface, rinsing water-filled bags if necessary, and tamping down cabbage again until brine bubbles up to cover surface. If brine sinks below level of cabbage, add enough additional brine (1 1/2 tsp. salt dissolved in 1 cup water) to cover cabbage.
Taste sauerkraut after 5 days to see whether it's ready. If you like it, put on the lid and chill. For a zingier flavor, let it develop for up to 4 weeks before chilling. Sauerkraut keeps, chilled and submerged in brine, up to 6 months.