An electric kettle may release visible steam before it switches off because hot water evaporates even below its boiling point. A visible cloud near the spout is tiny droplets that form as warm water vapor cools in the surrounding air. Many kettle shutoff designs respond to steam from vigorous boiling, which may occur a little later.
Steam appears before a rolling boil
As water heats, its evaporation rate increases. Warm, moist air leaving a spout can condense into the familiar white mist before all the water is vigorously bubbling. Seeing a little mist is not a precise thermometer.
What triggers automatic shutoff?
Many simple kettles channel boiling steam toward a heat-sensitive switch. A bimetallic element can trip, interrupting electrical power once the intended temperature conditions are reached. Some newer kettles use different electronic controls, so designs vary.
What the photograph shows
The glass electric kettle pictured is actively boiling, with bubbles in the water and a plume rising above the spout. This is the stage when a steam-responsive shutoff mechanism would generally be expected to respond; the exact switch timing cannot be determined from a still photo.
When to check the appliance
If the kettle repeatedly fails to stop during a full rolling boil, disconnect it once safe, let it cool, and consult the manufacturer. Keep the lid properly closed, observe the fill limits and avoid placing hands above the spout. Do not bypass switches or safety devices.
Frequently asked questions
Is white steam actually water vapor?
Pure water vapor is invisible. The white cloud is made of condensed tiny droplets suspended in the air.
Does an electric kettle always shut off at 100°C?
No. Water’s boiling temperature depends on atmospheric pressure and altitude; temperature-controlled designs also have different settings.
Related reading and sources
Explore this Wondelique guide and this related explanation. Learn more from the supporting reference.
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