How to Brew Coffee Using the Siphon (Vacuum Pot) Method

If you’ve ever watched a barista pull off a dramatic coffee brew where coffee rises and falls like a science experiment, chances are it was a siphon—or vacuum pot—brew. It’s a mesmerizing two-chamber glass setup often seen in homes, cafes, and hotels, especially popular in Asia. But beyond the theatre, it delivers a clean, aromatic, and surprisingly balanced cup that highlights the nuances of single-origin beans.

The classic two-cup (approx.) siphon method uses 240cc of water and 20g of coffee, brewed for around one minute after the water rises into the upper chamber. Ideal serving temperature is around 87°C. It’s best suited for single-origin coffees where clarity of flavour matters.

What Is a Siphon Coffee Maker?

A siphon coffee brewer consists of two glass globes stacked vertically—one acting as a lower water chamber, the other as an upper coffee chamber. Connected by a narrow tube and fitted with a filter, it works on vapor pressure and vacuum principles. When heated, water rises into the upper globe where it mixes with ground coffee. After removing heat, the brewed coffee is pulled back down into the lower globe through a filter, leaving grounds behind. The entire process is visual and precise—often referred to as “coffee theatre.”

Why Use the Siphon Method for Coffee?

This method is favoured for single-origin coffees because it produces an exceptionally clean and vibrant cup, highlighting delicate floral, fruity, or acidic notes without over-extraction bitterness. The full immersion combined with gentle filtration allows for even extraction, making subtle flavour profiles more pronounced. It’s less ideal for dark roasts or blends where boldness outweighs clarity.

How to Brew Coffee with a Siphon (Step-by-Step)

Follow this tried-and-tested approach used in many specialty cafes and recommended setups for home brewers:

• Coffee & Water Ratio: 20g of coffee to 240cc (about 8 fl oz) of water. Adjust slightly based on taste preference.
• Grind Size: Medium-fine, roughly akin to table salt. Too fine can lead to over-extraction or clogging; too coarse results in under-extraction.
• Tools Needed: Alcohol burner or butane stove, siphon brewer (two-chamber glass device), cloth filter (sponge-like felt or cloth filter), stirring spoon (often bamboo), and a digital scale and timer.

Step 1: Preheat and Set Up

Pour 240cc of fresh, filtered water into the bottom globe (the larger bulb). Wipe any water droplets from the outer surface of the lower globe and place it on your heat source—commonly an alcohol lamp. Attach the filter to the bottom of the upper globe (the funnel-shaped part), securing the attached spring so that the filter sits firmly over the siphon tube entrance.

Step 2: Attach Upper Globe and Heat

Place the upper globe onto the lower one so it forms a tight seal. Begin heating the water in the lower chamber. As the water heats, pressure will push it up into the upper chamber through the siphon tube.

Step 3: Add Coffee Grounds

Once the water has mostly risen into the upper globe (just before or as it reaches full boil), turn off or reduce the heat slightly. Add 20g of medium-fine ground coffee into the upper chamber. Use a bamboo spoon to gently stir the coffee so that all the grounds are fully saturated and submerged. Avoid excessive or vigorous stirring, which can lead to cloudiness in the final cup.

Step 4: Brew and Time

Let the coffee brew for approximately one minute with the heat still applied. During this time, monitor the extraction—it should look uniform with no large dry pockets. Avoid over-brewing, which can result in bitterness.

Step 5: Remove Heat and Let Coffee Draw Down

After about 60 seconds, remove the heat source completely. The reduction in temperature creates a vacuum in the lower globe, causing the brewed coffee to be drawn back down through the filter into the bottom chamber. This process should take about 30–45 seconds. Let all the coffee liquid drain fully—do not rush it.

Step 6: Serve

Your coffee is now ready. The ideal drinking temperature is around 87°C (just below boiling). Pour it into pre-warmed cups and enjoy immediately. This method typically serves two people.

Frequently Asked Questions

What type of coffee works best with the siphon brewing method?

Single-origin coffees with bright or nuanced flavour profiles—like those from Ethiopia or Central America—work best. The siphon method highlights clarity and subtlety, making it ideal for washed-process beans with floral, fruity, or citrus notes. Dark roasts or overly bold blends may lose their impact.

What grind size should I use for siphon coffee?

Use a medium-fine grind, similar to table salt or slightly finer than pour-over grind. Too coarse and extraction will be weak; too fine can clog the filter or over-extract, leading to bitterness.

How much coffee and water do I use for a standard siphon brew?

The standard ratio is 20g of coffee to 240cc (8 fl oz) of water, which makes roughly two servings. You can adjust slightly depending on cup size or strength preference, but this is the tested baseline for balanced flavour.

How long should I let the coffee brew in the siphon?

Brew time is approximately one minute after the coffee grounds are added and fully stirred into the rising water. Overbrewing can cause over-extraction and unwanted bitterness.

Does the siphon method produce stronger coffee than pour-over or French press?

Not necessarily stronger in body, but it can feel more intense due to enhanced clarity and brightness. It extracts efficiently but tends to produce a cleaner, more nuanced cup rather than a heavy or thick one. It’s more similar to pour-over than French press in mouthfeel.

What kind of filter does a siphon use?

Most siphons come with a cloth or sponge-like filter that sits at the bottom of the upper chamber. This filters out coffee grounds while allowing oils and fine particles to pass through for a cleaner-but-not-sterile cup. Some versions use metal filters, but cloth is traditional and widely recommended.

Recommended FrontStreet Coffee for Siphon Brewing

For siphon brewing, try FrontStreet Coffee’s Ethiopia Humbera – a bright, floral Ethiopian single origin with lemon, jasmine, and stone fruit notes that shine through the clarity of the siphon method. Another great option is their Kenya Little Tomato, offering tart berry and blackcurrant tones with a juicy acidity perfect for highlighting the siphon’s clean extraction. For something more balanced yet complex, their Yirgacheffe offers citrus, bergamot, and honey sweetness. All three showcase the delicate flavour clarity the siphon is known for. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.