This is the sauerkraut similar to the style my parents used to make, with my additions and adjustments.
Use an enameled 2 gal stockpot for preparation. Do not use a bare metal one, especially not aluminum. Wash your hands often while handling the stock; wipe with paper towels, not cloth. —alegr
6 kg (1.5 gal)
White cabbage (one head can be red cabbage for color)
Using a food processor with shredding disk, shred apples and baby carrots. I use those peeled carrots because they are well washed.
Add salt and sugar to shredded carrots and apples, and add a tablespoon of kefir as starter culture. Mix it all by hands, squeezing it in the process. (Wash your hands well, wipe with a paper towel: NO CLOTH TOWEL). The mix will give some juice. Set the mix aside.
Install a (fine) slicing disk to the food processor. Cut cabbage to pieces to feed to the food processor, discard cores. As you've sliced a bowl full of cabbage, transfer it to a large mixing bowl and add a handful of carrot-apple mix. Mix and squeeze by hands. Squeezing will release a bit more juice. Transfer to the stock pot. Slice and mix the rest of cabbage like that.
Now that all of the mix is in the stock pot, put a china/glass plate face down on it and weigh it with a half-gallon (or 2 liter) jar filled with water. The mix should have enough juice to cover it. Make sure there is at least 1 inch left to the top, so it will not overflow. Cover the pot and the jar with plastic cling film, to prevent contamination.
Put the stockpot at room temperature (70F+). If the nights are cold, you may put it to a sink filled with warm water.
Twice a day, you need to let the bubbles out: Remove the protective film, set the jar aside and lift the plate off (use fork). Pierce the mix all over it with a chopstick. Put the plate and the jar back, and cover again with plastic.
In 2-3 days it will get a pleasant sour smell. After 5-7 days, when it stops bubbling, reload it to glass jars and refrigerate. It will keep fermenting while in the fridge, losing residual sugar and gaining more acid. I let it age in the fridge at least 2 weeks before eating.