Liquid cooling mediums employed to immersion-cool electronic hardware devices. Such liquid cooling mediums have a flash point of at least 190° C., as determined according to ASTM D92, and a viscosity of 27 centistokes (“cSt”) or less at 40° C., as determined according to ASTM D445. Such liquid cooling mediums can be employed to immersion-cool such devices as computer servers, server motherboards, and microprocessors.