How to brew our coffee at home

Filter coffee at home is not difficult, but it is unforgiving of guessing. Four things decide the cup: the ratio of coffee to water, the grind, the water itself and the time. Fix those and you can brew the same good cup on a Monday as on a Sunday, which is more useful than occasionally brewing a brilliant one. So start with scales. Not a measuring spoon, not a scoop. Coffee is sold by weight and brewed by weight, and a spoonful of a light roast weighs noticeably less than a spoonful of a dark one. A cheap kitchen scale with a one-gram resolution changes more in your coffee than any new brewer will.

Water first

Coffee is about 98 per cent water, so the water is an ingredient. Lisbon tap water is drinkable but hard in most of the city, and hardness both mutes acidity and scales your kettle. A simple filter jug is enough. What you want is moderate mineral content — some magnesium and calcium to carry flavour, modest bicarbonate so the coffee's own acids are not neutralised. Distilled or fully softened water makes flat, hollow coffee, so more filtering is not better. Temperature matters almost as much: 92 to 94 °C for most of our coffees. If you have no thermometer, boil and wait 45 seconds with the lid off. Lighter roasts are less soluble and prefer the top of that range; a darker roast or a decaf will be softer a couple of degrees below it.

A cone recipe

This is the recipe we use for a V60-style cone, and the one we teach new staff. Rinse the paper with hot water before you start, both to remove paper taste and to warm the brewer. Grind medium, like coarse table salt, and adjust from there. Pour gently and keep the water level in the middle of the bed rather than running it down the sides.

Read the clock as information, not as a rule. If the water has drained by two minutes, the grind is too coarse and the coffee will taste sour and empty however good it is. If it is still sitting in the cone at four, the grind is too fine or you have agitated the bed too much, and you will get a dry, harsh finish. Sour and bitter are the two ends of one dial: sour is under-extraction, harsh bitterness and astringency are over-extraction. Change one thing at a time, and always the grind before anything else.

French press, simpler

• 60 g of coffee per litre — for a small press, 30 g to 500 g of water. Grind coarse.
• Add all the water at 94 °C, stir once to wet the grounds, put the lid on without plunging.
• Wait four minutes, break the crust and skim the foam and floating grounds off the top.
• Wait another five minutes for the fines to settle, then press the plunger just below the surface and pour slowly, leaving the sludge behind.
• Do not press all the way down and do not leave the coffee sitting on the bed; decant anything you are not drinking.
• Drip bags need only a mug: hang the bag, bloom with a little water, fill in two goes to about 200 g and lift it out at two and a half minutes.

Grind as close to brewing as you can, keep the bag closed and out of the fridge, and buy little and often. Freshness beats equipment.