How to Nail the Chemex Brew Every Single Time

By PURE EARTH COFFEE  ·  May 14, 2026  ·  Brew Better

Why the Chemex Rewards Precision More Than Any Other Brewer

The Chemex uses a thicker filter than most pour over methods — 20 to 30 percent thicker than standard paper filters. That thickness is the key to the Chemex's signature clarity. It strips almost all oils and fine particles from the brew, producing a cup that's exceptionally clean and crisp. The downside: it also slows down flow rate and requires more careful control of grind size, water temperature, and pour technique to avoid stalling the brew and creating bitterness.

Unlike the V60 or AeroPress, the Chemex is unforgiving of sloppy technique. The reward for dialing it in is a cup that showcases the delicate, nuanced notes of high-quality specialty coffee better than almost any other home brewer. That's why at PURE EARTH COFFEE, we reach for the Chemex when we want to highlight the floral, citrus, and stone-fruit characteristics of our Ethiopian Light/Medium Roast.

Equipment and Coffee You'll Need

Before you brew, make sure you have the right setup. For a 6-cup Chemex brew (approximately 600ml), you'll need:

• Chemex brewer (6-cup or 8-cup)
• Chemex bonded square filters (never use other brands — the fit matters)
• A burr grinder — this is non-negotiable for Chemex. A quality grinder like the Fellow Ode Brew Grinder will make the single biggest difference in your cup quality.
• A gooseneck kettle — the Fellow Stagg EKG Electric Kettle with temperature control is the benchmark here. Precision pouring at a controlled temperature is essential.
• A kitchen scale (accurate to 0.1g)
• Fresh specialty coffee — medium-light to light roast works best in a Chemex

Coffee ratio: 1:15 to 1:16 (coffee to water by weight). For 600ml of water, use 37.5–40g of coffee. Start at 1:16 and adjust from there based on taste.

Grind Size: The Most Common Chemex Mistake

The most frequent Chemex failure comes from grinding too fine. Because the thick Chemex filter slows flow, a grind that would work perfectly in a V60 will stall completely in a Chemex — leading to over-extraction and bitterness. You want a medium-coarse grind: slightly coarser than drip coffee, about the texture of raw sugar. If your total brew time exceeds 5 minutes, coarsen your grind. If it's under 3.5 minutes, go slightly finer.

This is also why burr grinder quality matters so much for Chemex. A blade grinder or a low-quality burr produces uneven particle sizes — some too fine, some too coarse — which makes dialing in the Chemex nearly impossible. Invest in a quality burr grinder and your Chemex results will transform. Check out our full coffee grinder collection for options at every price point.

Step-by-Step Chemex Brew Guide

Step 1: Boil and target temperature. Heat water to 200–205°F (93–96°C). If you don't have a temperature-controlled kettle, boil and let stand for 45 seconds off the boil.

Step 2: Rinse the filter. Open the square filter into a cone shape with three layers on one side (toward the spout). Place in the Chemex. Pour hot water through the filter to pre-wet it and eliminate paper taste. Discard the rinse water.

Step 3: Add coffee. Add your ground coffee to the wet filter. Give the Chemex a gentle shake to level the bed.

Step 4: Bloom. Start your timer. Pour 2x the coffee weight in water (if using 40g coffee, pour 80g water) in a slow spiral from center outward. This is the bloom — hot water releases CO2 from fresh coffee. Let it bloom for 45 seconds. If your coffee is very fresh, the bloom will be vigorous. If the bloom is flat, your coffee is stale.

Step 5: First main pour. At 45 seconds, pour slowly and steadily in a spiral, bringing the total water weight to about 300g. Maintain a slow, even pace. The goal is to keep the slurry level consistent — not to dump water in all at once.

Step 6: Second pour. At around 1:30–2:00, once the water level has dropped, pour the remaining water up to your target weight (600g). Again, slow and steady spirals.

Step 7: Draw-down. Let the brew complete draw-down. Total brew time should be 4:00–4:30. If significantly faster or slower, adjust grind size on your next brew.

Dialing In Your Chemex — Tasting and Adjusting

After your first brew, taste and diagnose. If the cup is bitter, harsh, or drying — grind coarser, or reduce brew time. If the cup is flat, thin, or sour — grind finer, or increase brew time slightly. If the cup tastes papery — you didn't rinse the filter adequately. If the cup is uneven or has a strange earthy note — check that your slurry level stayed consistent during pouring and that the filter didn't collapse against the Chemex walls during brew.

The Chemex rewards patience. Expect your first few brews to be calibration runs. By the third or fourth attempt, dialing in your specific coffee at your specific altitude will produce a cup that's genuinely difficult to beat at home. Explore our home brewing collection for everything you need to build a complete Chemex setup.

"The Chemex doesn't hide poor technique. It amplifies it. Which means when you get it right, you're brewing at a level most coffee shops don't achieve." — PURE EARTH COFFEE

Best Coffees for Chemex

The Chemex's clarity-focused extraction shines brightest with light to medium-light roasts where delicate aromatics and origin character are the star. Our Ethiopian Light/Medium — have the brightness, complexity, and clean finish that the Chemex showcases best. For medium roasts with more body and sweetness, the Nicaragua Medium Roast works beautifully. Avoid very dark roasts in the Chemex — the thick filter strips oils that darker roasts rely on for body, leaving you with a flat cup.