Rinse sauerkraut and squeeze dry. Place half of the sauerkraut in a slow cooker. Cut sausage into 2-inch lengths. Place in slow cooker. (I've made this with bratwurst -cooking it before putting in crockpot) Continue to layer in slow cooker, in order, apples, brown sugar, salt, pepper and, if desired, caraway seeds (I never use them). Top with remaining sauerkraut. Add apple juice. DO NOT STIR. Cover and cook on high for 3 to 3-1/2 hours or on low for 6 to 7 hours or until apples are tender. Stir before serving.