Inner container for electrically heated water boilers

An electrically heated water boiler comprises a chamber for receiving water to be boiled, a heating element 15 for boiling the water and arranged to be switched off by a steam-operated switch 12 in communication with steam in the chamber, an inner container 2 for receiving a food or drink product to be heated, the inner container having an outer wall 8 having ribs 16 arranged to be exposed to steam in the chamber, and the chamber having an opening 5 to atmosphere the size of which is variable so as to vary the amount of steam allowed to escape from the chamber. This variable opening enables the final temperature of the heated product to be controlled.