How to descale a kettle (and why it keeps coming back)

That chalky crust inside the kettle is limescale — calcium carbonate left behind when hard water boils. It is harmless to drink, ugly to look at, and expensive to ignore: scale insulates the heating plate, so the kettle works longer for the same boil and dies younger. Descaling is the rare appliance chore that takes ten active minutes and pays back visibly.

The method

Half water, half white vinegar, up to about the scale line — or a dedicated descaler per its own instructions, if you prefer the odourless route. Bring to the boil, switch off, and let it sit for an hour or so; heavy scale gets a second gentle warm pass rather than a harder scrub. Empty, rinse thoroughly, then boil-and-discard two full kettles of fresh water so the next cup of tea tastes like tea. Wipe the filter spout with a cloth while you are there. What you should never do: scrape enamel or heating plates with metal, or mix descalers — the vinegar method alone, patiently repeated, wins.

Why it keeps coming back, and the honest fixes

Scale returns because hard water is the tap's nature, not the kettle's fault. The habit that halves it: empty the kettle after use instead of letting last night's water evaporate onto the plate, and descale on a calendar rhythm — monthly in hard-water areas, quarterly elsewhere — before the crust becomes a geology. A boiling-water tap or filter jug changes the arithmetic but not the principle. This is the same slow-then-sudden appliance logic as dust on fridge coils and load discipline in washers: small chemistry, ignored, becomes the repair bill later — the house rule the someday-cost guide is built on.