Making your own sauerkraut is EASY! All you need is a nice head of cabbage (from your garden, or from the farmers’ markets right now), salt (either kosher or pickling salt, NOT iodized table salt), a large non-metal container like a plastic food-grade tub, or a ceramic crock roughly large enough to hold about twice the amount of cabbage you want to ferment, a clean, never-used plastic garbage bag, a sharp knife, a cutting board, water, and 2-weeks' worth of patience. Optional but useful stuff: a digital scale, canning jars and lids, and a large pot for hot-water canning.
To make sauerkraut you need 3 tablespoons of salt for every 5 pounds of shredded cabbage--this is why the scale comes in handy, but this “formula” is just an approximation. If you don’t have a kitchen scale you can figure out how much your cabbage weighs by getting on your bathroom scale with and without your cabbage! Anyway, here’s what you do:
First, make sure that your container is clean and sterilized. Clean with dish soap and water, then sterilize with a roughly 10% solution of bleach (Clorox) in water (1 part bleach to 9 parts water). Fill your container with this and let it sit for a half hour or so, then rinse thoroughly with cold water.
Next, take off any loose outer leaves from your cabbage, and cut off any brown bits from the stem end. Cut the cabbage into quarters and cut out the core. You can add the core pieces to your kraut if you like. Shred the cabbage and layer it in your tub or crock, sprinkling in the salt as you go. Pack down the cabbage tightly as you add more layers. This is an optional step, but I find it helps: for 5 lbs of cabbage add about a quart of a weak brine made with 1 ½ tsp salt per cup of water (6 tsp salt per 4 cups water. Your cabbage should make it’s own brine when the salt pulls out its own juices, but I’ve found adding a bit more brine helps the process along.) Your container should be roughly half-full of cabbage at this point (see below for why.)
Now, get out the clean garbage bag and place it on top of your salted cabbage. Carefully fill the garbage bag with cold water almost up to the top of your container, twist and tie it shut. The water-filled bag does two things: 1. It weighs down the salted cabbage, and 2. It prevents air from getting in. See, what you’re doing is actually salt-fermenting the cabbage. What you want to happen is for the good bacteria (lactobacilli) in the cabbage to grow in the salty brine. You want to keep out the air and any harmful bacteria (hence the water-filled bag.) Set your container in a cool place (65-72 ° F or so, like your basement) for two weeks. I find that with my bad memory and short attention span it helps to actually put a piece of tape on the container with the date you started, and put a reminder for yourself 2 weeks from now in whatever daily calendar you use to “check the kraut”.
Two weeks later: Open the bag and carefully dump out enough of the water so that you can remove the bag. The sauerkraut should smell and look like cabbage, but with a slightly fermented hint, and should be fairly crisp still. Sometimes the top layer gets a bit soft. If so, you can scrape this off and discard it. There shouldn’t be any mold if you’ve kept out the air properly. The cabbage in the brine should be fairly crispy with a pleasingly tart, salty, almost nutty taste. (Go ahead and taste it—raw sauerkraut is very good for you—this is a wonderful live food that’s great for the digestion. If you’ve heard of “probiotics” this is one of the cheapest, and easiest ways to put them into your diet.) At this point you can use the sauerkraut in your favorite recipes. Because of the salt I usually rinse the sauerkraut well before using it to cook with. You can either store it in its brine for a couple more weeks in the fridge, or can it in a hot water bath in the brine. (It’s acid enough that hot-water canning is ok for sauerkraut.) To can it place the sauerkraut in its brine in a pot, and bring the temperature up to a simmer, but don’t boil it. Pack the sauerkraut while hot into proper canning jars that you’ve sterilized in boiling water, leaving ½ inch of head room. Add the hot brine (juice) from the sauerkraut to the jars to cover the sauerkraut up to the head room mark. If you don’t have enough brine from the fermented cabbage, just make more brine using 1½ tablespoons of salt per quart of water, heated to boiling. Make sure the tops and sides of the jars are clean and dry using a clean paper towel. Place the lids on the jars, hand-tighten the rings, and process in a simmering hot water bath for 15 minutes for pint jars, 25 minutes for quart jars. (This comes from the book Putting Food By, by Janet Greene, Ruth Hertzberg, and Beatrice Vaughan, which is an invaluable source for preserving everything from your garden!) Once the sauerkraut cools the lids should seal: remove the outer rings and test by pressing down on them. If they don’t give, they’re sealed. If any don’t seal all is not lost, just store in the fridge, and use within a week or so. The properly canned sauerkraut should be good on your pantry shelf for several months. Enjoy!