Aluminum Foil

What side of the aluminum foil should be on the outside when I wrap something up in it to keep warm or cold? The shiny side or the dull? I was at a grill out last week and was told that the shiny side should be on the inside and the dull side of the aluminum foil should be on the outside. 

Ans:

The shiny side is slightly better reflector of heat. Face that side of the foil in the appropriate direction. To keep things cold, put the shiny side on the outside -- that will reflect incoming heat. To keep things warm, face the shiny side inward toward the hot food -- to reflect the heat that is trying to escape back into the food.

Note that people often bake potatoes with the shiny side out -- that is because it makes for a better (prettier) presentation. In reality, baking them that way reflects the incoming heat on the outside, slightly slowing the cooking process.