What makes Chemex different
The Chemex uses a bonded paper filter that is 20–30% thicker than standard pour-over filters. This removes almost all the oils and fine particles from your brew, producing an exceptionally clean, sediment-free cup with crisp acidity. That clarity is the Chemex's superpower — but it also means over-extraction shows up immediately as harsh bitterness.
The hourglass shape isn't just aesthetic. The wooden collar sits where the glass narrows, acting as an air vent so the water drains at the right speed. If you pour too aggressively or grind too fine, the filter will seal against the glass and stall the brew entirely.
The recipe
Start here and adjust based on taste:
- Dose: 30 g coffee to 500 g water (1:16.5 ratio)
- Grind: Medium-coarse — like raw sugar crystals
- Water temperature: 93–96 °C (200–205 °F)
- Total brew time: 4–5 minutes
The Chemex needs a coarser grind than most pour-over methods because of how slowly the thick filter drains. If your total brew time is under 3:30, grind coarser. Over 5:30, grind finer.
Step-by-step brew guide
1. Rinse the filter. Place the three-layered side of the folded filter toward the spout. Pour hot water through to rinse out the papery taste and preheat the brewer. Discard the rinse water.
2. Add your coffee and bloom. Pour 60 g of water (twice your coffee dose) over the grounds, saturating them evenly. Wait 45 seconds. This bloom lets CO₂ escape from freshly roasted beans — skipping it leads to uneven extraction.
3. Pour in stages. After the bloom, pour in slow circles from the centre outward, keeping the water level between 2 and 4 cm below the rim. Add water every 45–60 seconds as the bed drains. Aim for 3–4 total pours.
4. Finish at 4–5 minutes. If the brew finishes well under 4 minutes, the grind is too coarse. Over 5 minutes, go finer or reduce your dose slightly.
Common problems and how to fix them
Bitter or harsh
Almost always over-extraction. Grind coarser (move up one or two notches), reduce your water temperature by 2–3 degrees, or use a slightly lower dose. If the brew stalled and took over 6 minutes, the grind is the primary cause.
Weak or watery
Under-extraction. Grind finer, increase your dose to 32–34 g, or slow down your pour to give the water more contact time. Also check that you're using fresh coffee — beans more than 4 weeks past roast date extract less efficiently.
Brew stalling completely
Your grind is too fine and the filter has sealed against the glass. Grind noticeably coarser on your next brew. In the current brew, gently stir the slurry to break the seal — it will drain, but the flavour will be affected.