Siphon

A siphon — or vacuum pot — has two chambers. Water in the lower one is heated until vapour pressure forces it up a tube into the upper chamber, where the coffee is. When you remove the heat, the lower chamber cools, pressure drops, and the vacuum pulls the brewed coffee back down through a filter.

Why it makes good coffee

Two properties combine that most brewers cannot manage together.

Full immersion. All the coffee is in contact with all the water for the whole brew, so extraction is even in a way pour-over cannot match.

A proper filter. The vacuum pulls the coffee through cloth or paper, so the cup is clean rather than silty.

The result is clarity with an even, complete extraction — clean like a pour-over, even like an immersion.

The method

• 20 g coffee, medium grind, for 300 g water
• Water in the lower bulb, heat until it rises
• Add coffee to the upper chamber, stir gently
• Brew 60 to 90 seconds, stirring once more
• Remove the heat and let the vacuum draw it down
• The drawdown should take about a minute

Honest assessment

It is fiddly, fragile and slow, and it requires a heat source, a stand and a filter regime. Most of what it achieves can be reached with a good immersion brewer and a paper filter — a Hario Switch, for instance.

It is also genuinely spectacular to watch, which is a legitimate reason to own one.

Filter maintenance

Cloth filters must be rinsed thoroughly, stored wet in the fridge, and replaced every month or two. A dried-out cloth filter goes rancid and ruins the coffee.