My kettle boils and never switches off. What is wrong?
Two causes account for almost all of it and both are fixable. The first is a lid that is not fully closed, which lets steam escape into the room instead of down the internal channel, so the sensor never warms enough to trip. Push the lid down until the catch engages, every time, and note that this kettle's dual-angle lid has a partly open position for pouring that is not the closed position, which is an easy mistake to make daily. The second is scale or debris blocking the steam channel itself, which is maintenance rather than a defect.
How do I descale it, and how often?
Whenever you can see deposit, and on a glass kettle you can, which is a genuine advantage over a steel one where you discover it years later. Cosori's routine is 1 cup of vinegar or lemon juice with 2 cups of water: bring it to the boil, leave it for 2 hours, wipe the inside with a cloth, then rinse with clean water and dry with a soft cloth. Every boil leaves behind the dissolved calcium and magnesium in the water, deposited on the hottest surface, the element in the base. Scale is a thermal insulator, so as it thickens the kettle takes longer to boil the same volume and the element runs hotter than designed, which is how kettles eventually fail. The same deposits can block the steam channel that runs the shut-off, so descaling is a safety job as well as a performance one.
Will the water taste of plastic?
It should not, and that is the practical benefit you notice first. A new kettle with plastic in the water path typically needs several boil-and-discard cycles before the faint plastic note disappears from the first cup, and some never quite lose it. A glass-and-steel path has nothing to contribute, which is why the water tastes of nothing but water and why this design suits anyone drinking tea or filter coffee, where the water is most of what you are tasting.
Is boil-dry protection the same as the auto shut-off?
No, and mixing them up causes a lot of confusion. The steam switch is what stops the kettle when the water boils. Boil-dry protection is a separate safeguard that cuts power if the kettle is switched on without enough water. A kettle can have working boil-dry protection while its steam switch is not tripping, and vice versa.
Will the glass crack?
Not from ordinary use, but resistance to thermal shock is not immunity. Do not pour cold water into a kettle that has just boiled, and never let it boil dry. And it remains glass in a kitchen: a knock against a tap, a stone worktop or another pan will do what a knock does to glass, and that is the one respect in which this is genuinely more fragile than a stainless equivalent.
How fast does it boil?
Cosori says half a litre boils in under three minutes, and at 1500 watts that is about as fast as a standard US outlet allows. Speed is one of its real strengths. If it starts taking noticeably longer than it used to, that is usually scale on the element rather than a failing kettle, so descale it before assuming the worst.
