Genuine Isinglass sturgeon bladders come from the gallbladders of the Russian sturgeon. The sturgeon bladders we offer are of the finest quality and free of blood. The sturgeon gallbladders are a by-product of the caviar industry. Making sturgeon glue from the gallbladders is a somewhat lengthy but simple process of soaking the bladders overnight, heating over a double boiler, then straining the mix through a gauze filter. Once you have completed this procedure, you will have an exceptional glue. Complete instructions come with each order.