So I bought a used Kuhn Rikon Pressure cooker (the original, not the duromatic). I have no idea how pressure cookers work let alone how Kuhn Rikon works, but I did buy Kuhn Rikon because from what I read, it traps in steam and volatiles better than conventional pressure cookers due to its valve system and doesn't vent
So I decided to try chicken stock today and the instruction manual says that while heating it up, first air will escape, then then pressure valve on top will rise to the red mark and close up the valve. There was a lot of hissing from steam escaping and sputtering at first, then after a while when the red mark appeared, the steaming and sputtering reduced but the hissing sound was still apparent. I thought one of the key features of a kuhn rikon was the lack of hissing. Is there just simply *less* hissing than conventional pressure cookers or is there not supposed to be any hissing at all? Is there something defective with what I bought?