Remove any bruised or damaged exterior leaves from your cabbage, and then slice it in half crosswise. Remove the cabbage's core, and then slice the cabbage into strips no wider than ⅛-inch thick.
Toss cabbage, salt, and caraway seeds in a large mixing bowl and let it rest for about 20 minutes, or until the cabbage softens and releases a little juice. Then squeeze the cabbage with your hands to soften it even further and help it to release more juice.
Transfer the cabbage to your jar when it has become limp and has released ample juice. Pack the sauerkraut tightly into your jar, using a kraut pounder or a wooden spoon, so that the cabbage continues to release its liquid and no air bubbles remain.
Continue packing the cabbage into the container until the cabbage is completely submerged in its liquid.
Weigh the cabbage down with a glass fermentation weight so that the brine fully submerges it. Seal it tightly with a fermentation seal or airlock, and allow the cabbage to ferment at room temperature and away from direct sunlight for at least 1 month or until done to your liking. Transfer it to the fridge, where it will keep at least 6 months and up to 1 year.