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A GOOD cup of coffee is all about balance. Coffee contains more than 1000 flavour compounds, including some that provide the fruity, earthy and chocolatey aromas we detect in our noses and others responsible for the acidity, bitterness and astringency we detect in our mouths.

The challenge is to extract a rich brew of desirable flavour compounds without overextracting those that make the drink bitter and overpowering. The roasting and grinding of the beans, the temperature of the water, the ratio of ground coffee to water and the time they are in contact all play a part, but different brewing methods all make coffee with different characteristics.

Espresso machines drive hot water through finely ground coffee at around 9 atmospheres of pressure. This extracts a much higher concentration of chemicals from the coffee, including a large amount of oils, giving the drink a creamier mouthfeel and slowing the release of flavour.

You can’t replicate this at home without an expensive machine. If you like your coffee strong, perhaps the best approximation is a , in which steam pressure pushes boiling water through a bed of ground coffee into a chamber at the top.

I normally use a cafetière, or French press, which makes it easy to adjust the variables to your taste. I find that about 6 grams of coarsely ground coffee for every 100 millilitres of water and a brewing time of around 4 minutes give the best results.

The optimum temperature for brewing is considered to be anywhere between 85°C and 93°C, but a recent trend has seen the rise of a different approach: cold brewing. This means steeping the ground coffee in water at room temperature or cooler. Cold-brew coffee is usually served cold, but it can also be heated up – in contrast to iced coffee, which is brewed hot then cooled down.

Enthusiasts say cold brewing results in a different flavour profile, often described as smooth and mellow with less acidity, less bitterness and . A flurry of recent appears to back this up. Chemists have found cold-brew coffee has similar levels of caffeine to hot-brew coffee, but a .

At low temperatures, chemicals are extracted from the ground beans much more slowly, so the coffee is typically left to steep for at least 8 hours. But show good results can be achieved in as little as 2 hours at room temperature, and longer brewing may lead to more bitterness.

Pour the water over the coffee in a cafetière and stir. Place the lid on and leave it for an hour, then stir again and leave for another hour. Press the plunger before serving. I take mine with ice and milk – it is the perfect way to perk up and cool down on a hot day.

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