Evaporated milk is heated in its can to a temperature well above 200F in order to sterilize the milk. A cooked or burnt flavor is the outcome. The metal of the can also imparts an off-flavor. Another canned product, condensed milk, does not have to be sterilized because its high sugar content (over 40 percent) serves as a preservative by hindering bacterial growth. Of course, that much sugar does not make condensed milk all that appealing either.
** Asian Recipes