Let cabbage heads stand at room temperature for about 24 hours to wilt. This causes the leaves to soften slightly and become less likely to break when cut.
Wash the head and remove outer leaves. Cut heads into quarters and remove the cores.
With a sharp knife, shred 5 pounds of cabbage 1/8 to 1/4 inch thick.
Place the shredded cabbage in a large mixing bowl and sprinkle with about 3 tablespoons of the salt.
Mix the salted cabbage with your hands or with a stainless steel spoon and let it stand 3 to 5 minutes.
Wash a 10 gallon crock with soapy water, rinse and scale it with boiling water.
Pack salted cabbage into the crock. A brine will form as you press the cabbage down.
Repeat the shredding and salting in 5 pound lots until the crock is filled to within no more than 5 inches of the top.
The brine should cover the cabbage. If it does not, add additional brine by heating 1 1/2 tablespoons of salt with 1 quart of water.
Cool the brine to room temperature before adding it to the crock.
To cover the cabbage and weight it down to keep it submerged in the brine, fill a clean, large, heavy plastic bag, such as heavy duty trash bag, with water and lay it over the cabbage.
Fit the bag snugly against the inside walls of the crock to prevent the surface of the cabbage from being exposed to air. This will prevent the growth of a yeast film or mold.
Add more water to the plastic bag, if necessary, to keep the cabbage submerged.
Seal the bag with a twist tie. Cover the crock with plastic wrap.
Fermentation will take place from 3 to 6 weeks depending on the room temperature. The ideal temperature is 75 degrees F. At 75 degrees F fermentation will take about 3 weeks, at 70 degrees F, 4 weeks, at 65 degrees F, 5 weeks and at 60 degrees F allow about 6 weeks.
Tightly packed in covered containers, the kraut can be safely kept in the refrigerator for several months. If you do not have space, can the sauerkraut.
Canning the sauerkraut :
Bring the kraut to a simmer. Do not boil.
Pack it into clean, hot jars, leaving 1/2 inch headspace. Seal.
Process in a water bath canner for 20 minutes for quarts or 15 minutes for pints.
Start counting the processing time when the water in canner starts to boil.