Pickle Pebbles have been specifically designed for fermenting vegetables and fruits in Mason jars. Pickle Pebbles take the guess work out of your lacto-ferments by ensuring your veggies stay below the surface of the brine, thereby eliminating exposure to oxygen which is the main cause of spoilage and mold. While a single Pickle Pebble is often enough to keep veggies below the brine, they can also be stacked to provide extra weight. Pickle Pebbles are made of non-iridized soda glass which is completely inert and guarantees that no other substances leach into your ferment.