How a Siphon Coffee Maker Works and How to Use One

If you’ve ever watched someone make coffee with a glass contraption that looks like a chemistry set, you’ve seen a siphon (or vacuum) coffee maker. It’s dramatic, precise, and loved by coffee enthusiasts for its theatrical brewing process—but how does it actually work? And more importantly, how do you get a great cup out of it?

To brew one good cup using a standard 3-cup siphon: use 120ml water and 15g coffee. For 2 cups, use 240ml water and 30g coffee. Total brew time should be under 1 minute once extraction begins. Adjust dose slightly to taste.

What Is a Siphon Coffee Maker?

Also known as a vacuum or syphon pot, the siphon coffee maker has been around for over 200 years. It’s a glass device consisting of an upper and lower chamber, often heated with an alcohol lamp. The unique design uses vapor pressure and gravity to brew coffee, combining immersion and filtration in one striking process. Because of its complexity and visual appeal, it’s considered more of a specialist tool than everyday equipment.

How Does a Siphon Brewer Make Coffee?

The siphon’s brewing process relies entirely on pressure difference. Here’s the science: you heat water in the lower chamber until it boils, creating vapor pressure that pushes water up a tube into the upper chamber where coffee grounds are added. Once brewing completes, removing the heat source causes a pressure drop, and the brewed coffee is pulled back down into the lower chamber by gravity. For a faster drawdown, you can cool the lower chamber quickly—like wiping it with a damp cloth.

Parts of a Siphon Coffee Maker

• Upper Chamber: Holds coffee grounds and facilitates mixing & extraction.
• Lower Chamber: Contains water and collects the finished brew.
• Lower Chamber Stand: Supports the entire setup.
• Upper Chamber Lid: Keeps heat and pressure inside.
• Filter Cloth: Made of fabric, filters coffee grounds.
• Alcohol Burner: Primary heat source.
• Protective Shield: Covers the burner for safety.
• Stirring Tools: Spoon or paddle for agitation.

Siphon Coffee Ratios and Measurements

For consistent results, siphon brewing follows fairly precise dosing:

• Water per cup: 120ml (standard cup size).
• Coffee per cup: 15g (about 1 heaping coffee spoon).
• 2-cup brew (3-cup siphon): 240ml water, 30g coffee (3 scoops).
• 3-cup brew: 360ml water, 45g coffee.
• 5-cup brew: 600ml water, 75g coffee.

Siphons typically show volume markings—each mark represents 120ml. These numbers help you hit the right water level for your desired yield.

Step-by-Step: How to Use a Siphon Coffee Maker

Here’s the full workflow for making coffee with a 3-cup siphon using freshly ground beans:

1. Grind Your Coffee

Grind fresh coffee beans to a medium-fine consistency, similar to table salt. You’ll need around 15g per cup (e.g., 30g for 2 cups).

2. Prepare the Siphon

Take apart the siphon. Secure the filter cloth in the upper chamber using the attached hook—it should sit just above the narrowing tube.

3. Add Water to the Lower Chamber

Pour fresh or filtered water into the bottom chamber up to the appropriate level for your brew size. For 2 cups, fill to the 240ml mark (typically the second major line).

4. Assemble & Add Coffee

Attach the upper chamber to the lower one while it’s off the heat, letting it rest at an angle. Add your ground coffee (e.g., 30g for 2 cups) into the upper chamber once it’s in place.

5. Heat & Initiate Brew

Place the alcohol burner under the lower chamber and light it. Heat until the water boils vigorously and begins to rise into the upper chamber due to vapor pressure. The majority (~95%) of the water should move upward, though a small amount may remain behind.

6. Submerge and Bloom

Once boiling subsides, stabilize the upper chamber so it sits straight and fully seated. Let the water fully saturate the grounds. Once at least 1/3 of the water has entered the upper chamber, reduce the flame slightly. Then, stir the coffee gently in a clockwise direction for 10 seconds to ensure all grounds are wet (this is your bloom period).

7. Brew & Stir Again

Start timing. After 40 seconds (the bloom/steep phase), stir the slurry again, this time counterclockwise, for 5 seconds to ensure even extraction.

8. Draw Down the Coffee

Remove the heat source immediately. The reduction in temperature and pressure will cause the brewed coffee to be sucked back down into the lower chamber. To speed this up, wipe the lower chamber with a damp cloth to help it cool faster. The entire extraction and drawdown process should take less than 1 minute from when you first combine water and grounds.

9. Serve

Your brewed coffee is now in the lower chamber. Add sugar or milk to taste if desired.

Cleaning Your Siphon Brewer

Cleaning is straightforward but essential:

1. Gently tap the upper chamber near the tube opening to loosen coffee grounds.
2. Tap around the glass to release any remaining particles.
3. Pour out the grounds and rinse the inner walls.
4. Rinse the filter area thoroughly under running water.
5. Remove the filter spring, then clean it separately.
6. Wipe and squeeze dry without twisting too hard.
7. Use a brush and mild cleaner on the upper parts, careful not to damage the glass.

Store the filter cloth in water to prevent oxidation if not used frequently.

Frequently Asked Questions

How much coffee do I use per cup in a siphon?

Use 15g of coffee per 120ml (1 cup) of water. For 2 cups (240ml), use 30g; for 3 cups (360ml), use 45g; and for 5 cups (600ml), use 75g. The standard coffee scoop that comes with most siphons holds 10g.

What grind size is best for siphon coffee?

Use a medium-fine grind, similar to table salt or slightly finer than pour-over. This allows for proper extraction during the 40 to 60 second brew cycle without over- or under-extracting.

Does the order of adding coffee matter in a siphon?

No, not significantly. You can add coffee before heating (and wait for water to rise), or add it after water enters the upper chamber. Timing adjustments may vary—bloom time may increase to around 45 seconds if coffee is added later.

How long should a siphon coffee brew take?

Total brew time (from mixing to drawdown) should be under 1 minute. The initial heat-up and water transfer takes longer, but the actual coffee-water contact time is around 40–50 seconds after stirring.

How do I clean a siphon filter?

Remove the filter cloth or spring by releasing the hook. Rinse it thoroughly under running water and use a soft brush if needed. Store it in water if not used often to avoid rusting.

Recommended FrontStreet Beans for Siphon Brewing

For siphon brewing, try FrontStreet Coffee’s Ethiopia Humbera—a bright Ethiopian offering with notes of blueberry, jasmine, and citrus—or the Brazil Queen Manor, which brings chocolate, caramel, and a smooth body perfect for balancing siphon extractions. For something more floral and delicate, the Yirgacheffe offers lemon, bergamot, and stone fruit tones. All shine with the clarity and body siphon brewing highlights. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.