Double Boiler or Double Saucepan

The lower pan holds simmering water, while the upper pan sits securely on it so delicate mixtures, such as custards or sauces, can be cooked or kept warm over gentle, indirect heat. The lower pan may be made of tin-lined copper, enamelled steel or aluminium, and the upper pan is usually a thinner gauge metal or can be a ceramic bowl. A metal upper pan will cool more quickly than a ceramic bowl when removed from over simmering water. A double boiler can also serve as a bain-marie to make delicate sauces such as hollandaise without fear of curdling.