Five mistakes that ruin good coffee at home

The five most common mistakes are using boiling water, old coffee, measuring by eye, a grind that does not suit your coffee maker and a dirty coffee maker. All of them can be fixed without spending more. Together they make more of a difference than buying a new coffee maker.

1. Boiling water or tap water

Water at a full boil scalds the coffee and brings out bitter flavors. The ideal is between 90 and 96 °C. Without a thermometer, just turn off the heat and wait about 30 seconds before pouring.

Coffee is almost entirely water, so water quality counts. Use purified water; tap water can leave a chlorine taste.

2. Old coffee, or coffee ground long ago

Coffee loses aroma from the moment it is roasted, and much faster once ground. Coffee from two months ago will never taste like coffee from this week. Buy a little at a time, and if you can, grind right before brewing.

3. Measuring by eye

One day it comes out weak and the next too strong, and it seems like the coffee changed. The rule is simple: about 10 grams per 200 ml cup, roughly two level tablespoons. Always use the same spoon and the same cup to measure.

4. A grind that does not suit your coffee maker

Each method needs its own grind. Too fine for your coffee maker and it turns out bitter; too coarse and it tastes weak. Coarse for French press and cold brew, medium for drip and olla, fine for moka pot and espresso.

5. A dirty coffee maker

Coffee oils stick to the carafe, the filter and the reservoir. Over time they go rancid and pass that taste on to every cup. Wash everything after each use, and once a month run water with a splash of vinegar through the machine, followed by two cycles of plain water.

And if you have coffee left over

Drink it cold over ice rather than reheating it. Coffee that is reheated or left on the warming plate turns bitter within minutes.