How to Brew Syphon Coffee at Home

A coffee syphon brews by vapour pressure and vacuum. Heating water in the lower chamber forces it up into the upper chamber to steep with the grounds; removing the heat cools the lower chamber and the resulting vacuum draws the coffee back down through a cloth filter. A typical recipe is 24 g of medium-ground coffee to 360 g of water, steeped for about 60 seconds. New cloth filters should be boiled before first use and stored submerged in water.

Syphons have a reputation for being difficult that they don't really deserve. There are more parts than a V60 and there's an open flame involved, so it looks like a procedure. Once you've done it twice it's about as demanding as making a pot of tea, and it's a good deal more entertaining.

What's actually happening

Heat the water in the bottom chamber and the air above it expands, pushing the water up the tube into the upper chamber where the coffee is. Take the heat away and the bottom chamber cools, the air contracts, and the resulting vacuum pulls the brewed coffee back down through the filter.

The coffee never boils. It sits in the upper chamber at around 90 to 93 °C, which is exactly where you want it. Full immersion, then filtered on the way out, which is why the cup has body but no grit.

Prepare the cloth first

This is the step people skip and then wonder why their syphon coffee tastes odd.

A new cloth filter comes with sizing in it from manufacture. Boil it for a few minutes in water before its first use, ideally with a spoonful of used coffee grounds, then rinse it.

After every brew, rinse the cloth thoroughly and store it submerged in water in the fridge. Do not let it dry out. A dried cloth locks in old coffee oils that go rancid, and you'll taste it in the next brew and every one after. Change the cloth every couple of months, or sooner if it starts to smell.

If that sounds like more upkeep than you want, paper filters fit the same mechanism at £6 for a hundred. The cup comes out cleaner and a bit lighter.

The brew

24 g of coffee to 360 g of water, ground medium, roughly what you'd use for a V60 or slightly coarser.

1. Fill the lower chamber with 360 g of hot water. Starting with pre-boiled water saves several minutes of waiting.
2. Fit the filter into the upper chamber and hook the chain down through the tube so it sits centred.
3. Seat the upper chamber loosely and light the burner. Once the water starts moving, push the upper chamber down to seal it.
4. Let the water rise. A little will stay in the bottom, which is normal.
5. Add the coffee and stir gently, just enough to wet all of it. This is the first of two stirs.
6. Steep for 60 seconds.
7. Stir again, briefly, then take the heat away.
8. The coffee draws back down over 30 to 60 seconds. You want a level, domed bed of grounds left in the upper chamber.

That dome tells you it went well. A crater in the middle means you stirred too hard at the end.

Getting it wrong, and fixing it

Drawdown takes ages. Grind is too fine, or the cloth needs replacing.

Coffee tastes flat. Usually under-stirred at the start, so some grounds never got properly wet.

It tastes of old coffee. The cloth. Boil it, or replace it.

Which syphon

The Technica at £123 is the two-cup classic and comes with the frame and alcohol burner. The Next at £105 does five cups. Keep a spare filter mechanism around, since it's the part that eventually wears.

For where all this came from, our history of the syphon goes back to the 1830s.

Frequently asked questions

How does a coffee syphon work?
Vapour pressure pushes heated water up into the upper chamber to steep with the grounds. Removing the heat creates a vacuum that draws the coffee back down through a filter.

What grind size is best for syphon coffee?
Medium, about the same as a V60 or slightly coarser.

How do I clean and store a syphon cloth filter?
Rinse thoroughly after each brew and store it submerged in water in the fridge. Never let it dry out.

Can I use paper filters instead of cloth in a Hario syphon?
Yes. They fit the same mechanism and give a slightly cleaner, lighter cup.

How long does syphon coffee take to brew?
About four to five minutes with pre-boiled water, including a 60 second steep and the drawdown.