12 hours ago, Smithy said:
1. The poor cabbage heads were already semi-frozen. (It's been well below freezing for more than a week.) I couldn't tell it while shredding them, but when I started mixing in the salt I could tell that there may have been partial freezing. At any rate, it's all cold!
In our kraut related family knowledge, the best kraut was made after the first frost hit the cabbage. It made them sweeter and fermented better.
Also Penn State:
The best sauerkraut is made from cabbage that is harvested after frost. Cool weather increases the production of natural sugars in the cabbage that are needed for fermentation. It is best to wait until the first frost to make your sauerkraut.