Replacement Butterfly Dump Valve Assembly for the Fermentasaurus. The Fermentasaurus has been designed with a sanitary butterfly valve with stainless gate. This butterfly valve has been designed so that no threads are immersed in liquid when the Fermentasaurus is in use. Many fermenters on the market use ball valves which are notoriously difficult to sanitise as the ball valve assemblies have small cavities in them that fill with liquid and are near impossible to clean without disassembly. For Generation 2 Fermentasaurus.