How much brine should be above the Dunk'R?

The Dunk’R should be covered by 1-inch of brine. The brine surface should not extend above the shoulder when fermenting foods that expand during fermentation. Kraut, carrots and beets may expand as much as 1-inch, raising the brine surface and Dunk’R.

To decrease expansion, firmly-pack shredded foods, reducing oxygen pockets in and around the food. Detailed information is here.