How to Clean a Coffee Maker

If your morning cup has started tasting flat, sour or oddly burnt, the beans may not be to blame. Coffee leaves behind oils that turn rancid, and the water passing through the machine drops traces of minerals inside the tank and tubes. Over time those two things change the taste, slow the brewing and can shorten the life of the appliance. The good news is that cleaning a drip coffee maker takes very little effort once it becomes routine.

Signs your machine needs attention

• The brew cycle takes noticeably longer than it used to.
• Coffee tastes harsher even with the same beans and grind.
• You can see white or chalky crust around the water outlet or inside the reservoir.
• The carafe has a brown ring that rinsing does not remove.
• There is a musty smell when you open the lid of the water tank.

After every pot

A few seconds after each brew prevents most problems. Throw away the used grounds and filter while they are still warm, rinse the brew basket and the carafe in hot soapy water, and leave the lid of the reservoir open so it can air-dry. A damp, closed tank is exactly where mould likes to settle.

The monthly descaling cycle

How often you need to descale depends on how hard your tap water is and how much coffee you make. In areas with chalky water, monthly is a sensible starting point; with soft water, every few months may be enough. Always check the maker's manual first, since some brands specify their own descaling solution and a particular routine.

1. Empty and rinse. Remove any old water and grounds, and put a clean paper filter in the basket to catch loosened flakes.
2. Fill with solution. Pour equal parts white vinegar and fresh water into the reservoir up to its full mark. If you prefer, use a commercial descaler mixed exactly as its label says instead.
3. Run half a cycle. Start a brew and switch the machine off when roughly half the liquid has passed through. Let it sit for about half an hour so the warm solution can work on deposits inside the heater.
4. Finish the cycle. Turn the machine back on and let the rest of the solution run into the carafe. Discard it.
5. Flush with clean water. Fill the tank with plain water and run a complete cycle. Repeat at least twice more, using a fresh filter each time, until no hint of vinegar remains in the smell or taste.

Citric acid powder dissolved in water is another option with less odour. Whatever you choose, stick to a single product per session.

Carafe, basket and warming plate

Glass carafe

For stubborn stains, add a little warm water, a spoonful of baking soda and a handful of ice cubes or coarse salt, then swirl. The grit scrubs the inner walls without scratching. Rinse well. Check the manual before putting the carafe in a dishwasher, as not all are suitable.

Thermal carafe

Insulated jugs keep coffee hot but also hold onto odours. Fill with hot water and a little baking soda, leave for an hour, then rinse and let it dry upside down with the lid off.

Filter basket and lid

Coffee oils collect in the corners of the basket and under the shower head that drips water onto the grounds. A soft toothbrush dipped in soapy water reaches those spots easily.

Warming plate

Wait until the plate is completely cold and the machine is unplugged. A cloth dampened with soapy water, followed by a dry one, removes splashes. Avoid abrasive pads, which can scratch the coating.

Pod machines and espresso makers

Single-serve brewers and espresso machines usually have narrow pipes, pumps and needles that are more sensitive than a basic drip maker. Many of them have a built-in descaling mode that you start through a button combination described in the manual. Follow that procedure rather than improvising, and use only the solution the manufacturer recommends. Pod holders and drip trays, however, can simply be washed in warm soapy water.

Quick reference

Safety notes

• Unplug the machine before wiping anything near the heating plate or the power switch.
• Never immerse the base of an electric coffee maker in water.
• Do not mix vinegar with bleach or with other cleaning products.
• Keep descaling solutions out of reach of children and label any bottle you decant.

Once the coffee maker gleams, the rest of the kitchen tends to look a bit tired by comparison. Our guide on cleaning an oven with kitchen staples uses the same cupboard ingredients, and if the counter is crowded with gadgets you never touch, decluttering one room at a time is a gentle place to begin.