Here are some of the great features of Fermenting Jar Weights

Fermenting Jar Weights, Glass canning jar weights especially for use in lacto fermented preserving in a jar. This product was developed to keep the vegetables below the level of the liquid in the jar, which is really about the only cause of possible failure when using lacto fermenting preserving methods. These weights will fit a wide mouth canning jar. There will be approximately 1/2 " space all around the margin of the weight where it does not cover the food. This is to allow the gas to come to the top and not get stuck under the weight. Also note, on some spongy food or food that has a tendency to float, more than one weight might be needed to keep the food submerged. You get 7 weights of the wide mouth size which are about 2 1/3 inches in diameter. They are made of non iridized glass which is completely inert and will not leach chemicals into your ferments.