1. Remove outer leaves from cabbage. Quarter cabbage heads lengthwise; remove cores. Using a mandoline, food processor, or large chef's knife, finely shred cabbage. Measure 2 1/2 pounds shredded cabbage.

2. Place the 2 1/2 pounds shredded cabbage in a large ceramic crock, glass container, or plastic food container that holds at least 1 gallon. Add pickling salt and sugar. Using very clean hands or tongs, toss cabbage with pickling salt and sugar. Let stand 10 minutes. Using a clean, heavy plate that fits just inside the container, press plate down on cabbage. Let stand at room temperature for 2 to 24 hours, tossing cabbage and pressing plate down on cabbage every hour or until enough liquid is released to cover cabbage by at least 1 inch. (If cabbage does not release enough liquid, add enough water to cover in a ratio of 1 cup water to 1 teaspoon pickling salt.)

3. Place a large resealable plastic bag filled with 1 quart water plus 4 teaspoons salt (or a clean 1-gallon jug full of water) over the plate to weight it down. Cover container with a clean dishcloth or loose-fitting lid. Place container in a cool place out of direct sunlight to ferment. At temperatures between 70ºF and 75ºF, fermentation will take 3 to 4 weeks; at 60ºF to 65ºF, fermentation will take 5 to 6 weeks. The sauerkraut is ready when it has a slightly crunchy texture and pleasantly tangy flavor.

4. Every 2 or 3 days, replace dishcloth with a clean dishcloth, skim off any scum that forms on surface of cabbage, and clean and replace plate. If any discolored cabbage appears at the top, remove and discard it. If the water level gets too low, add enough water to cover in a ratio of 1 cup water to 1 teaspoon salt.

5. Transfer undrained sauerkraut to canning jars or airtight containers; seal and label. Store in the refrigerator up to 2 months.

Apple-Caraway Sauerkraut:

Prepare as directed, except add 1 large or 2 small Granny Smith apples, peeled, cored, and shredded or finely chopped, and 1 tablespoon caraway seeds to the cabbage with the salt in Step 2.