Skip to content
CoffeeHQ

hybrid method

Siphon (vacuum) brewing

A two-chamber glass brewer that uses vapour pressure and then a vacuum. Water in the lower globe is heated until expanding vapour pushes it up a tube into the upper chamber, where it steeps with the coffee at close to full immersion. Taking the heat away cools the lower chamber, the trapped air contracts, and the resulting vacuum draws the brewed coffee back down through a filter — cloth in most traditional models — leaving the grounds behind.

Coffee-to-water ratio
55–70 g per litre (typically 65)
Grind
Medium to medium-coarse. Finer than a French press despite the full immersion, because the filter is doing real work rather than just holding a plunger.
Water temperature
88-96 celsius (typically 92)°C
Contact time
60-120 seconds (typically 90)
Skill level
advanced

Descriptive grind labels like this are illustrative starting points, not precise measurements — the same label can mean different particle sizes on different grinders. See the grind size guide for how to dial this in on your own equipment.

Expected flavour profile

Full immersion at a stable, comparatively high temperature extracts efficiently, and the filter then removes the fines — so the cup is unusually clear for an immersion brew and fuller-bodied than paper pour-over, particularly with the cloth filter most traditional models use. Clarity and body at the same time is what the method is valued for, and it is a genuine consequence of separating the steep from the filtration rather than making one do both.

Equipment

Common problems

  • Water rises only partly, or falls back before brewing
  • A dry crust of grounds floating on top, so only part of the dose extracts
  • The draw-down stalls with liquid stuck in the upper chamber
  • Bitterness from leaving the heat on during the steep

Seat the upper chamber squarely so the seal holds, and stir when the water arrives so nothing floats dry. If the draw-down stalls, the filter is clogged or the grind is too fine. Take the heat away as soon as the steep is done rather than holding it there.

Cleaning & maintenance

Rinse both chambers immediately; a cloth filter must be rinsed thoroughly with no detergent and then kept wet — stored in clean water in the fridge, or frozen. A dried-out cloth goes rancid from the oils it holds and will taint the next brew.

Glass is the fragile part: the chambers crack from thermal shock or from being over-tightened. Replace the filter cloth and its spring clip when the cloth stops sealing against the rim.

Roasts and coffees that suit it

Named regional traditions built on this brewing method — the same mechanism, put to culturally distinct use.