Roots & Harvest 5L Water Seal Crock

5L Fermentation Crock with Lid & Weights. Create delicious sauerkraut, pickles, and more with these ceramic, water-seal crock sets. Water Tight Seal:?áWhen the gutter is filled with water, and the lid is placed on top, an airtight seal is formed to begin the fermentation process. Water keeps out surface molds but allows CO2 to escape. The water-seal makes it easy to ferment without having to constantly check the food. You simply add water as it evaporates to keep the seal intact.