An expert drinker's view Just keep it simple

There is an episode of the hit TV series Breaking Bad in which Walter White, high school chemistry teacher turned drug kingpin, meets a new colleague in front of a tangle of clamps, pipes and slowly dripping flasks.

- Esther Addley

When the other character lets him taste what he has been brewing, White is stunned. "My God, that is the best coffee I've ever tasted," he says. "Why the hell are we making meth?"

Coffee may not be - quite - as addictive as methamphetamines, but to some of its aficionados, the hunt for the perfect hit of bean, roast, grind and brew is as seductive as any illicit drug. That search took another step forward this week with new research into the optimal height and speed from which to pour water on to coffee grounds.

Thanks to "avalanche dynamics", researchers from the university of Pennsylvania found, water tipped from a goose-necked kettle with a higher, slower pour can result in stronger pour-over coffee - the name given to filter coffee made by hand rather than a machine.

The perfect cup of coffee, of course, is as individual a preference as the perfect partner, and if yours is a spoonful of Mellow Birds with a slug of milk and four sugars, by all means you do you. But if we can agree that bad coffee certainly exists - boiled to a bitter sludge on a roadside diner hotplate, perhaps, or tipped into tepid milk by an indifferent barista - it is possible to refine the process to make a better one.