Aluminum Foil: The Myth of the Shiny SideThe engineering reason behind the two textures

From the show

Why it looks like that

Understanding the physical difference between foil sides reveals the truth about their cooking properties. To roll aluminum thin enough without tearing, manufacturers press two sheets through rollers simultaneously. The side touching the roller becomes polished while the inner side remains matte due to friction. This engineering constraint means the visual difference has no impact on heat conduction or cooking results.