These weights are actually Weck reusable Glass Lids. Made of the highest quality glass, they contain NO BPA! (Bisphenol A), lead, mercury or cadmium.
Lids come in 3 sizes: small, medium and large. Small = 70mm, Medium = 90mm,
Large = 110mm
If you are using one of our Weck fermenting jars, choose small for the 1 litre jars and medium for the 1.5 litre jars.
For the Ball 2 litre jars and Fido jars you can use the small weight but due to the width of the shoulders there will not be a full coverage of the surface. In this instance you can use vegetables such as cabbage leaves or strips of carrot peel to cover the surface and then weight this with the small weight.
Note that the fit is tight and if you are fermenting very liquid foods, the weight will sink unless there is sufficient food mass in the jar to hold it up.