Wash your hands and mason jar with soap and hot water.
Cut the cabbage into pieces that will fit in your food processor. Using the grater blade (the one with holes), grate the cabbage. You can also use a hand grater, or finely shave the cabbage with a knife.
In a bowl or cup, mix the miso with the water to make a thin paste.
Combine all ingredients in a large bowl and massage with your hands until the juices are released. This is your chance to get a really good hand workout. Squeeze out those juices!
Pack the juicy cabbage mixture tightly into the glass mason jar with a tight fitting metal lid. The plastic lids don't seal well. The juice should cover the cabbage completely, leaving an inch of space at the top of the jar so the kraut can expand as it ferments.
Seal tightly, clean the outside of the jar and store in a cool, dark place on a tray to catch any overflowing juices as leakage will likely occur.
After at least 3 days, Open with care. Refrigerate after opening. Flatten top as you use it, less air touching it is best. This will naturally preserve it for months in the fridge. Darkening at the top is normal.