Pressure cookers have been around for quite some time. In 1679, a French physicist and mathematician Denis Papin made the first version of the pressure cooker, (though he called it a steam digester at that time) with a large cast iron vessel and a lid that would fit tightly and then could be locked, completely sealing the cooker. In the earlier versions there was no safety valve and once during a demonstration of the pressure cooker it burst and that is how Papin came up with the safety valve. Over the years pressure cookers have evolved greatly and today we see modernized versions of the earlier pressure cooker, which are smaller in size and much safer to use. Due to an increased safety, they are highly popular amongst chefs.