Siphon Coffee

Siphon coffee is brewed in a vacuum pot: two glass chambers, one above the other, joined by a tube. Heat the lower chamber and vapour pressure pushes the water up into the top chamber, where it brews with the coffee. Take the heat away and, as the lower chamber cools, the vacuum pulls the coffee back down through a filter. It’s part science experiment, part theatre, and it makes a very clean, aromatic, light-bodied cup. Here’s how it works, Hario’s recipe and the surprisingly long history.

The short version

• Two chambers: heat pushes the water up, cooling pulls the coffee down.
• Hario’s guide: 15–17 g of medium-fine coffee to 250 g of water.
• Brew for about 70 seconds in the top chamber, then take the heat away.
• Cloth or paper filter, for a very clean cup.
• Invented in Europe from 1827 on, and loved in Japan’s coffee houses.

How does a siphon work?

1. Up: heating the sealed lower chamber builds vapour pressure, which pushes the water up the tube into the top chamber.
2. Steep: you add the coffee to the hot water up top and it brews, with the heat kept low so the water stays there.
3. Down: take the heat away, the lower chamber cools, and the partial vacuum pulls the coffee back down through the filter.

Strictly, it isn’t a true siphon at all: it works by vapour pressure and a vacuum, which is why it’s also called a vacuum pot.

What do you need?

• A siphon brewer: two glass chambers, a stand and a filter
• A heat source: an alcohol burner, butane burner or halogen heater
• A filter: cloth, paper or, on some models, a glass rod
• Coffee, a grinder, scales, and a bamboo paddle or spoon to stir

How much coffee and water should I use?

Hario UK’s syphon guide:

	Amount
Coffee	15–17 g, ground medium-fine
Water	250 g
Stir	3–5 gentle circular stirs once the coffee is in
Brew	70 seconds on low heat, then heat off and 3 more stirs

Hario’s global guide puts the coffee in the upper bowl first, heats for about one minute once the water has risen, then turns off the heat and lets the coffee come down on its own.

What grind size should I use?

Medium-fine. Too fine and it can clog the filter and stall the drawdown; too coarse and it tastes thin. Adjust from there.

How do you brew siphon coffee, step by step?

1. Soak the cloth filter in warm water, fit it in the top chamber and hook its chain to the bottom of the tube.
2. Pour 250 g of water into the lower bowl and dry the outside of the glass.
3. Heat it, with the top chamber resting in the bowl at an angle. Once the water starts to boil, seat the top chamber firmly.
4. When the water has risen, add 15–17 g of medium-fine coffee and stir gently three to five times.
5. Lower the heat so the water just stays up top, and brew for 70 seconds.
6. Turn off the heat and give it 3 good stirs. The coffee is pulled down through the filter.
7. Remove the top chamber carefully and pour.

Brew mode on this page times the brew and drawdown for you.

Why isn’t my siphon working?

Problem	Likely cause	Try
Water won’t rise	Top chamber not sealed	Seat it firmly once the water is near boiling
Drawdown stalls	Grind too fine, or a clogged filter	Grind coarser; clean or replace the cloth
Bitter, harsh	Too much heat, or brewing too long	Turn the heat down and shorten the brew
Thin, sour	Grind too coarse, or too short	Grind finer, or brew a little longer

A short history of the siphon

• 1827–1830s, Germany: the earliest vacuum brewers appear. Wikipedia credits Johann Nörrenberg, who described one in 1827; Hario UK credits the 1830s German maker Loeff with the earliest known design.
• 1841, France: Madame Vassieux of Lyon patents the twin-globe design, two glass globes held in a frame, that most people still picture.
• Around 1840, Scotland: a vacuum coffee machine is credited to Napier, an early relative of the siphon. Wikipedia names James Robert Napier and 1840; other sources name his father, the engineer Robert Napier.
• Balance siphons: a side-by-side variation, the Belgian balance siphon, also follows the same principle.
• Japan: Hario began making syphons in heatproof glass in the 1940s, and says the syphon was the first household product it ever sold; in 1946 it developed an all-glass vacuum pot modelled on America’s Cory brewer. Japan later started the Japan Siphonist Championship, in 2003.

Siphon vs other brewing methods

	Siphon	French press	Chemex
How it brews	Full immersion, then vacuum drawdown	Steep, then press	Pour-over
Filter	Cloth or paper	Metal mesh	Thick paper
Cup	Clean, light, aromatic	Heavy, full	Very clean
Effort	High, with a heat source	Low	Medium

How do you clean a siphon?

Let everything cool. Empty the grounds from the top chamber, rinse the glass, and rinse the cloth filter well. I’d keep a cloth filter damp in a covered container in the fridge between uses, and replace it when it stays stained or smells stale.

General guidance only. Siphons use an open flame or heater, hot glass and pressure: never leave one unattended, let the glass cool before handling, and always follow the instructions that come with yours.

Siphon vs other methods

• Belgian balance siphon: the side-by-side version.
• Cona vacuum brewer: a classic British vacuum brewer.
• Napier vacuum machine: an early Scottish relative.
• French press: full immersion without the theatre.

Explore every vacuum brewer in the vacuum chapter.