Natural aluminum is a soft, porous metal with deep pores that can accumulate contaminants, break down, and actually leach onto Foods. Fat Daddio's aluminum bakeware is anodized to ensure superior durability and a lifetime of baking confidence. The result is a beautiful, aluminum bakeware with better release and clean up. A professional, abrasion resistant pan that will not chip, flake, or chalk. Fat Daddio's pans will not discolor like natural aluminum and are protected from all acidic Foods and detergents. With Fat Daddio's bakeware you get all the benefits of aluminum with the superior performance of anodizing. Fat Daddio's bread pans are made of 18 guage aluminum and come in a variety of sizes. Hand wash.