The Chemex is a classic pour-over brewer known for its elegant design and remarkably clean cup. Invented in the 1940s by chemist Peter Schlumbohm, it combines form and function in one of coffee’s most enduring tools. The thick filter removes more oils and sediment than other pour-over methods, producing coffee that tastes bright, smooth, and clean. Many people swear that a Chemex makes the perfect cup of coffee.

If you landed on this page first, you may want to start with our Complete Guide to Pour-Over Coffee for a deeper look at why pour-over brewing creates such clarity and control

What Makes the Chemex Different

The Chemex stands apart because of its extra-thick paper filter—about 30 percent thicker than most. That filter traps more oils and fine sediments, resulting in coffee with a crystal-clear body and elevated brightness. The shape of the Chemex also contributes to its distinctive flavor profile: the wide neck and hourglass body allow heat to dissipate slowly, keeping the brew consistent from start to finish.

The result is a cup that’s smooth, aromatic, and free of bitterness. It’s perfect for those who prefer nuance and clarity over heavy texture and thick mouth feel.

What You’ll Need

• Chemex brewer (6-cup or 8-cup models are most common)
• Chemex paper filter (bonded square or circle)
• Freshly roasted whole-bean coffee
• Burr grinder (for consistent grind size)
• Gram scale
• Gooseneck kettle (for controlled pouring)
• Timer
• Filtered water heated to about 200 °F (93 °C)

Recommended Recipe

This recipe makes about two medium cups of coffee. The Chemex can easily scale up, so increase proportionally if you are brewing for more people.

Coffee to Water Ratio: 1:16
Coffee: 40 grams
Water: 640 grams total
Water Temperature: 200 °F (93 °C)
Brew Time: About 4 to 5 minutes

Step-by-Step Instructions

1. Prepare your filter and brewer

Open the Chemex filter so that three layers are on one side and one layer on the other. Place it in the brewer with the thicker side laying over the spout. Rinse the paper filter with hot water before brewing. This may help remove any traces of paper taste and will also preheat your Chemex. It also helps the filter stay in place during brewing. Discard the rinse water before adding your ground coffee. Make sure the filter did not collapse into the spout.

2. Measure and grind

Weigh 40 grams of coffee and grind it medium-coarse, slightly finer than for a French press but coarser than for a Kalita or V60. The grind should feel like coarse sand or kosher salt.

3. Add coffee and start your bloom

Add the ground coffee to the filter and shake gently to level the bed.
Start your timer and pour 80 grams of water (twice the weight of the coffee grounds) evenly over the grounds to saturate them completely. Allow the coffee to bloom for 45 seconds as it releases CO₂.

4. Continue pouring gradually

After the bloom, pour the remaining water slowly and evenly in small, steady amounts. Aim to keep the coffee bed evenly saturated without over-agitating the grounds. Pouring too aggressively or from too great a height can make the fines settle to the bottom and stop or slow the drawdown.

Finish adding all your water by about the 3:30 mark, and allow the brew to finish dripping by 4 to 5 minutes total.

If your brew takes much longer than that, the grind probably is too fine. If it drains too quickly, the grind is too coarse. Adjust accordingly next time.

5. Swirl, serve, and enjoy

Once the dripping stops, remove the filter and discard it. Swirl the Chemex gently to mix the layers evenly, then pour and enjoy.

Temperature Adjustments by Roast Level

The Chemex’s thick filter and slower flow rate accentuate acidity and sweetness. Adjusting water temperature helps balance those elements based on your roast.

Roast Level Water Temperature Flavor Result
Light Roast 200–205 °F (93–96 °C) Bright, crisp cup with clean citrus or floral notes
Medium Roast 195–200 °F (90–93 °C) Balanced sweetness and round body
Dark Roast 185–190 °F (85–88 °C) Smooth, mellow cup with chocolate or caramel tones

If your coffee is within three days of roasting, extend the bloom phase by 30 to 45 seconds to let the coffee de-gas fully before continuing your pour. After the bloom, the coffee bed should always be wet.

Fine-Tuning Your Brew

• If your brew is too slow: Coarsen your grind slightly or pour more gently to maintain flow.
• If your coffee tastes sour: Use hotter water or a finer grind.
• If your coffee tastes bitter: Lower the water temperature slightly or coarsen the grind.
• If your brew lacks sweetness: Extend your bloom or increase total brew time by 15 to 20 seconds.

Roaster’s Insight

At I Have a Bean, every bag is roasted and shipped the same day you order. Fresh coffee releases more gas especially at the beginning of a brew, which creates a livelier bloom. That burst of CO₂ can actually prevent proper extraction. The fix is simple: if your beans are within three days of roasting, extend the bloom phase by another 20 to 30 seconds to let the coffee de-gas fully. You’ll see the bed sink a bit. That extra time helps you unlock the full aroma, clarity, and sweetness of truly Just Roasted coffee.

Pro Tip: Avoiding a Stalled Chemex Brew

If your Chemex suddenly stops dripping mid-brew, don’t panic. This usually happens because the paper filter has collapsed against the glass spout, creating an airtight seal. When that happens, air can’t escape through the spout, so water stops flowing through the coffee bed.

How to fix it:
Gently lift one edge of the filter near the spout just enough to break the seal and allow air to flow again. The brew should resume immediately.

To prevent it in the future, make sure the three-layered side of the filter is facing the spout and that the spout itself remains open. Insert a chopstick, straw, or long thin spoon handle into the spout during brewing to keep a small air gap.

This small adjustment prevents stalling and ensures smooth, consistent extraction every time.

Common Questions about the Chemex

Why are Chemex filters so thick?
The thicker filter removes oils and fine particles, which gives the coffee a remarkably clean taste and a smooth finish.

Can I reuse a Chemex filter?
It’s not recommended. The paper fibers have absorbed oils from the previous brew, slowing flow rate and affecting cup clarity.

What’s the ideal grind for Chemex?
Medium-coarse, about the texture of coarse sand or kosher salt. Too fine, and the brew will stall. Too coarse, and the coffee will taste thin.

Final Thoughts

The Chemex is timeless for a reason. Its thicker filter and elegant design make it easy to produce coffee that is both refined and full of character. When paired with freshly roasted beans, the results are clear, sweet, and deeply satisfying.

If you’d like to compare results across different pour-over styles, check out our Kalita Wave 185 Brew Guide and Hario V60 Brew Guide, or start from the top with our Complete Guide to Pour-Over Coffee.

Ready to brew a Chemex worth sharing?
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