Chiffon cakes are baked in a tube pan, which is pretty important for the structure of an egg-based cake. The tube pan allows the batter to cling to the side of the pan, giving it plenty of room to rise and will also allow you to cool the cake upside down. Cooling the chiffon cake upside down helps the cake to cool while keeping all the bubbles and air in the cake rather than it becoming condensed by gravity during cooling.