bain marie pot
A bain marie consists of a smaller pot inside a larger one. The larger pot is filled with a liquid, typically water, while the substance to be heated goes in the smaller pot. The bain marie prevents the material in the smaller pot from rising above the boiling point of the liquid in the larger pot. The maximum temperature of the smaller pot can be adjusted by changing the liquid in the larger pot; adding salt to water will result in a higher boiling point, for example, while adding alcohol will lower the boiling point.