How to Brew Coffee with a Chemex: Step-by-Step Guide

If you’ve ever tried making coffee with a Chemex and ended up with weak, under-extracted, or overly bitter results, you’re not alone. Many home brewers struggle with the right grind, water amount, or timing. The Chemex is a beautiful and functional pour-over device, but it requires precision to get it right. This guide walks you through the exact steps used by experienced brewers to consistently produce clean, balanced coffee with a Chemex.

To brew with a Chemex, use 50–60g of coffee beans and 1200–1400g of water. Grind the beans to a French press-like coarseness, then pour in stages: first a bloom with twice the coffee’s weight in water (e.g., 100g for 50g beans), wait 30–45 seconds, then pour the rest over 2:30–3 minutes. Use a medium-coarse grind and a gentle circular pouring technique to avoid edge channeling.

What You’ll Need to Brew with a Chemex

Before diving into the steps, let’s confirm what tools and measurements you need. The standard Chemex brew uses 50–60g of coffee beans and 1200–1400g (1.2–1.4L) of water. That’s roughly a 1:20 to 1:23 coffee-to-water ratio—ideal for a clean, light-to-medium bodied cup. Your grinder should be set to a coarseness similar to what you’d use for a French press. That means a medium-coarse grind, which allows for even extraction without over-exposing delicate flavors to too much water.

Step-by-Step: Brewing Coffee with a Chemex

1. Heat Your Water & Grind the Coffee

Start by heating 1200–1400g of water. While the water heats, weigh out 50–60g of coffee beans and grind them to a French press-like coarseness. This grind size is essential—it’s coarse enough to slow down extraction but fine enough to allow proper flavor release during the pour.

2. Prepare the Filter & Preheat the Chemex

Open the Chemex filter and place it in the top of the brewer with the folded side facing the spout. Pour a small amount of hot water through the filter to wet it completely—this removes any paper taste and preheats the glass. You can also pour some hot water into your serving cup to keep it warm.

3. Add Coffee Grounds & Bloom

Discard the rinse water from the Chemex (not your cup), then add the ground coffee into the filter. Give the coffee a gentle shake to settle it evenly. Start your timer and pour about twice the weight of the coffee in hot water—e.g., 100g of water for 50g of coffee—to bloom the grounds. Let it sit for 30–45 seconds. This step releases gases trapped in the coffee and starts even extraction. Be careful not to pour water on the edges of the filter.

4. Pour in Stages for Full Extraction

After the bloom, continue pouring in slow, controlled circles, starting from the center and moving outward. Keep the water level steady and avoid pouring on the filter’s edges. Your goal is to finish pouring all 1200–1400g of water within 2:30–3 minutes. This pacing ensures even saturation and optimal flavor extraction.

Why These Steps Matter

The bloom step is critical for releasing CO₂ from freshly roasted coffee, which can block water and lead to uneven extraction. Pouring gently from the center avoids channelling—where water finds the path of least resistance and over-extracts some grounds while under-extracting others. Timing your total brew to 2:30–3 minutes ensures the coffee isn’t over- or under-extracted, balancing brightness, sweetness, and body.

Common Mistakes to Avoid

• Using too fine a grind (like espresso)—it will clog the filter and over-extract.
• Pouring too fast or unevenly, which leads to channeling.
• Skipping the bloom or not waiting long enough (30–45 seconds).
• Rushing the overall brew time—anything faster than 2:30 often means under-extraction.

Frequently Asked Questions

What is the ideal coffee-to-water ratio for Chemex?

The recommended ratio is around 1:20 to 1:23, meaning 50–60g of coffee to 1200–1400g of water. This produces a balanced cup with clean flavors and moderate strength.

What grind size should I use for Chemex?

Use a medium-coarse grind, similar to what you’d use for a French press. This allows for proper water flow and even extraction without over- or under-extracting the coffee.

Do I really need to bloom the coffee?

Yes. Blooming (pouring hot water equal to twice the coffee’s weight and waiting 30–45 seconds) releases trapped CO₂, which helps ensure even saturation and better flavor development.

How long should a Chemex brew take?

The total brew time—including bloom—should take about 2:30 to 3 minutes. Going faster often means under-extraction; slower can mean over-extraction.

Can I use any coffee beans in a Chemex?

Yes, but lighter to medium roasts tend to perform best, highlighting clarity and acidity. Dark roasts can work but may taste flatter due to the Chemex’s clean filtration.

Why is my Chemex coffee weak or bitter?

Weak coffee is often due to under-extraction (too little contact time or too coarse a grind). Bitterness usually means over-extraction (too fine a grind, too slow pour, or too much contact time).

Recommended FrontStreet Coffee Beans for Chemex Brewing

For Chemex brewing, FrontStreet Coffee’s Brazil Sidra offers a balanced profile with chocolate and peanut notes, perfect for beginners. Their washed Yirgacheffe brings bright citrus and floral tones, ideal for exploring fruity profiles. Both beans are easy to brew and highlight the Chemex’s clean extraction. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.