Thoroughly clean and scald the containers and utensils you will be using. Never use metal containers or utensils. Metal and fermentation don't mix!
Wash, drain and then cut your cabbages into halves or quarters.
Grate, shred or chop cabbage. You can do this by hand or with a food processor. Pieces should be about the size of a quarter, or smaller.
Grate carrots. Peel and grate and ginger. Mince garlic, if using.
With wooden spoon or very clean hands, mix the shredded cabbage, carrots, garlic and ginger with the sea salt, and toss and mix thoroughly until salt dissolves.
When juice starts to form on the cabbage from tossing, mix in the caraway seeds (if desired) and starter culture (if using).
Pack the cabbage and other veggies firmly and evenly into clean quart-size Mason jars or a large fermenting crock until liquid comes out of the cabbage freely. Leave 2 inches of room at the top of the jars or 4-5 inches of room at the top of a crock.
Make sure juice covers the cabbage completely! (This does not always happen unless the cabbage is fresh from the garden)
If needed, make additional brine by putting 1 1/2 Tbsp. of sea salt into 1 quart of boiling, purified water. Dissolve salt and cool brine to room temperature before adding to the cabbage.
Once cabbage is immersed in brine water, use a glass fermenting weight to keep the cabbage down under the brine. If you do not have a fermenting weight, put a freezer bag filled with water or even stones on top of the cabbage. (I use 2 large bags, one inside the other so that if the bag breaks, it will not water down the cabbage into a tasteless mess.) The cabbage must be completely submerged.
Close the jars with airlock lids, or very loosely applied canning lids. This will keep air out of your kraut and keep the jar from building up too much pressure.
Cover the jars with a clean towel and them in a cool (but not cold) area where the temperature will be between 65–75 degrees F. Fermentation will begin within a day, depending upon the room temperature.
Check jars after 2 days. Scoop any scum off the top (it is harmless), and repack. Check every 3 days and repeat as necessary.
After 2 weeks, sample the kraut to see if it tastes ready to eat. The flavor will continue to mature for the next several weeks.
Refrigerate the sauerkraut to extend its shelf life.