The Best Grind Size for Chemex Coffee
The best grind size for Chemex coffee is medium-coarse — roughly the texture of coarse sand or kosher salt. That’s noticeably coarser than what you’d use for most other pour-over drippers, like a V60.
Why Chemex Needs a Coarser Grind Than Other Pour-Over Methods
The reason comes down to the filter. Chemex uses a thick, bonded paper filter that’s about 20-30% denser than a standard pour-over filter — see our coffee filters guide for more on how filter material and thickness change extraction. That thicker filter is what gives Chemex coffee its signature clean, bright cup — it strips out more oils and fine particles than a typical filter — but it also slows water flow considerably.
If you use a grind that’s too fine for a Chemex, water can’t pass through the dense filter fast enough, and the coffee sits in contact with the water far too long, over-extracting and turning bitter or muddy. Go too coarse, on the other hand, and water rushes through before it can properly extract, leaving you with a thin, weak, under-extracted cup. Medium-coarse is the sweet spot that balances the filter’s slower flow rate against a reasonable total brew time.
Target Drawdown Time as Your Grind-Size Check
A reliable way to check whether your grind is right is to time the total drawdown (from your first pour to the moment all the water has drained through): aim for roughly 4.5 to 5.5 minutes for a full-sized Chemex brew. If your coffee is draining much faster than that, go slightly finer next time. If it’s dragging on well past 5.5 minutes, go slightly coarser.
Grinder Starting Points
If you’re using a home burr grinder, a good starting point is a setting toward the coarser end of your drip range — for example, around 20-25 on a Baratza Encore, though exact numbers vary by grinder model. Treat any specific setting as a starting point, not a fixed answer, and adjust based on your drawdown time and how the coffee actually tastes. For the broader logic behind grind size and why coarser particles need longer contact time, see our coffee grind size guide.
The Best Beans and Roast Level for Chemex
Because the Chemex’s thick filter produces such a clean, oil-light cup, it tends to flatter lighter and medium roasts especially well — the clarity that method produces highlights a coffee’s origin character, acidity, and more delicate flavor notes rather than muting them the way a fuller-bodied method like French press would. If you enjoy brighter, more nuanced coffees (fruity, floral, or tea-like notes are common in good light-roast Chemex cups), this is the brew method that shows them off best.
That said, medium and medium-dark roasts also brew well in a Chemex and tend to produce a smoother, more comforting, chocolatey cup — it’s a matter of what flavor profile you’re after, not a strict rule.
How to Brew Chemex Coffee, Step by Step
- Boil water and grind your coffee to a medium-coarse setting.
- Rinse the filter. Place the paper filter in the Chemex and rinse it with hot water, then discard the rinse water. This removes any papery taste from the filter and preheats the glass vessel — a step especially worth doing with unbleached filters.
- Add coffee and level the bed. Add your ground coffee to the rinsed filter and give the Chemex a gentle shake to level it out.
- Bloom. Place the Chemex on a scale, tare it, and start your timer. Pour roughly twice the weight of your dry coffee in water (for example, about 40g of water for 20g of coffee), pouring in a circular motion to saturate all the grounds evenly. Let the coffee bloom — off-gassing visibly — until about the 1-minute mark. See pour-over coffee bloom for why this step matters so much.
- Pulse-pour to your target weight. After blooming, continue pouring in stages — roughly 100g increments every 10-15 seconds, in a circular motion, avoiding the very edge of the filter — until you reach your total target brew weight (for example, around 800g of water for a fuller Chemex brew, scaled down for smaller batches).
- Let it fully drain, then serve. The whole process, start to finish, should take about 5-6 minutes.
Common Chemex Mistakes
- Grinding too fine, which chokes the thick filter and leads to slow, over-extracted, bitter coffee.
- Skipping the filter rinse, which can leave a papery taste in the final cup.
- Pouring too fast or off-center, which channels water straight through the bed without evenly saturating all the grounds.
- Ignoring drawdown time. If your total brew consistently finishes well outside the 4.5-5.5 minute range, that’s a more reliable signal to adjust your grind than trying to judge it by eye alone.
FAQ
What grind size is best for pour-over in general vs. Chemex specifically?
Most pour-over methods (like a V60) use a medium grind, while Chemex specifically needs a medium-coarse grind because its thicker, denser filter slows water flow more than a standard pour-over filter does. If you use your regular V60 grind setting in a Chemex, it will likely brew too slowly and taste over-extracted.
How do I make perfect coffee using a Chemex?
Use a medium-coarse grind, rinse the filter first, bloom the coffee for about a minute, then pulse-pour in stages to your target weight, aiming for a total drawdown time of 4.5-5.5 minutes. Adjust grind size based on whether your drawdown runs faster or slower than that window.
What is the best coffee to use with a Chemex?
Light to medium roasts tend to shine most in a Chemex, since the clean, oil-light cup the thick filter produces highlights bright, nuanced flavor notes well. Medium-dark roasts also work fine and produce a smoother, more chocolatey cup — it comes down to which flavor profile you prefer.