Grease down the sink: why it goes wrong — and what to do instead

Warm grease stays liquid just long enough to make it through the sink. A metre or so along, in the cold pipe, it congeals against the pipe wall and traps everything that follows: coffee grounds, food scraps, soap residue. Over months that builds a layer that narrows the pipe — until one day the drain stops running, usually at exactly the wrong moment.

Rinsing with hot water looks like the fix, but mainly moves the problem: the grease simply congeals a stretch further along, where the pipe is colder and you can no longer reach. Washing-up liquid breaks grease down only temporarily too; once the water cools, it sticks to the wall anyway.

What does work is simple. Pour cooled frying fat and oil into a bottle or jar for the bin, wipe pans and plates with kitchen paper first, and put coffee grounds in the bin instead of down the sink. Rinsing with hot water stays useful — as maintenance against the thin film, not as a disposal route.

If the sink is already draining slowly, tackle it before it closes up completely: plunger on, empty the trap. If that fails, having a sink drain unblocked costs € 95-225. If the grease problem keeps coming back — say, in a household that cooks a lot — preventive jetting (€ 95-175 per service) washes the entire pipe clean again; all rates are in the price index.