How to use a Chemex, step by step

Quick answer: how to use a Chemex

To use a Chemex, fold a Chemex filter into the top, rinse it with hot water, add coarsely ground coffee, wet it for a 30 to 45 second bloom, then pour the rest of the water slowly in circles. Use water at 199 to 205 °F and about 1 gram of coffee for every 15 grams of water.

For two mugs, that works out to 30 grams of coffee and 450 grams of water at 1:15.

What a Chemex is, and why the filter matters

The Chemex is an hourglass-shaped glass flask with a funnel-like neck, a wooden collar and a leather tie. Peter Schlumbohm invented it in 1941, and the Chemex Corporation makes it in Chicopee, Massachusetts. Wikipedia notes that one sits in the collection of the Museum of Modern Art in New York.

The filter is what sets it apart. Chemex filters are bonded paper, thicker than the filters in a drip machine, and Wikipedia says they remove most of the coffee oils. The result is a cup the article describes as much cleaner than other brewers make. A coarse grind keeps the water moving through that thick paper.

How to brew with a Chemex

1. Heat water to 199 to 205 °F. Heat more than you need, because some goes into rinsing.
2. Open a Chemex filter into a cone and set it in the top of the flask with the thicker, folded side against the pouring spout. The thick side keeps the paper from sinking into the spout, which lets air out as coffee drips in.
3. Rinse the filter with hot water. It warms the glass and washes out the paper taste. Pour the rinse water out through the spout, leaving the filter in place.
4. Weigh 30 grams of coffee and grind it coarse, like kosher salt. Add it to the filter and shake it level.
5. Set the Chemex on a scale and zero it. Pour 60 grams of water, twice the coffee's weight, evenly over the grounds and wait 30 to 45 seconds for the bloom.
6. Pour the rest slowly in circles, starting in the middle and working outward, keeping the water below the rim of the filter. Stop when the scale reads 450 grams.
7. Let it drain, lift out the filter and swirl the flask before pouring.

For other doses, our pour over coffee ratio chart gives the water for 15 to 30 grams of coffee at 1:13, 1:15 and 1:16.

Chemex troubleshooting

It drains too slowly

Grind coarser. If the stream stops entirely, check that the thick side of the filter sits over the spout; a thin side there seals against the glass and traps the air.

It tastes bitter

Grind coarser. The National Coffee Association links a bitter pour over to coffee ground too fine and pulling out too much.

It tastes flat or watery

Grind finer, since the NCA links a flat cup to a grind that is too coarse. If the flavor is right but thin, use more coffee for the same water, moving from 1:15 toward 1:13.

It tastes sharp and thin up in the mountains

At altitude the water is cooler than the recipe asks for. The next section explains what to do.

Using a Chemex at Colorado altitude

Wikipedia's high-altitude cooking page says water boils at about 203 °F at 5,000 feet, 197.4 °F at 8,000 feet and 193.6 °F at 10,000 feet. Denver sits at 5,280 feet, so a kettle there still reaches the 199 to 205 °F range. By the same rule of about 1 °F lost per 500 feet, a boiling kettle above roughly 7,000 feet cannot reach 199 °F at all.

In a mountain town, pour the moment the kettle boils, rinse the filter with boiling water so the glass is hot, and grind a step finer to make up for the cooler water. Our longer guide to high altitude coffee brewing explains why.

Colorado coffees that suit a Chemex

A clean, oil-free cup shows off a coffee's origin, which makes the Chemex a good match for single origins and lighter roasts. Some Colorado roasters we list, checked September 27, 2026:

• Middle State in Denver says it favors coffees that are complex, clean, bright and sweet, and names most single origins for the grower or washing station.
• Kaladi in Englewood sells an Ethiopia Yirgacheffe as a light roast.
• Bindle in Fort Collins lists the producer, process and elevation for each coffee, handy when you are learning what you like.

Buying from a roaster in this state keeps your coffee money with a Colorado roaster and crew you can name. Why local roasters matter. For a new single origin from a different Colorado roaster in every box, try the single origin subscription.

Chemex questions

What grind is best for a Chemex?

A coarse grind, about like kosher salt, which is what Wikipedia's Chemex article says is usually recommended. Go coarser if it drains slowly and finer if the cup tastes flat.

Can I use regular paper filters in a Chemex?

The Chemex is designed for its own bonded paper filters, which Wikipedia describes as thicker than drip machine filters and able to remove most of the coffee oils. A thinner filter changes the cup and fits the cone badly.

How much coffee do I use in a Chemex?

Use 1 gram of coffee for every 13 to 16 grams of water, the NCA's pour-over range. At our 1:15, that is 30 grams of coffee for 450 grams of water, or 20 grams for 300 grams.

What water should I use?

The NCA says to use cold water, filtered if possible, and to avoid distilled or softened water.

Sources

• Wikipedia, Chemex Coffeemaker (inventor, 1941, Chicopee, filters, grind, water temperature, MoMA)
• National Coffee Association, Pour-over coffee (ratio, bloom, contact time, grind fixes)
• National Coffee Association, Drip coffee (water quality)
• Wikipedia, High-altitude cooking (boiling points by elevation)
• Wikipedia, Denver (elevation)
• Roaster facts: the roasters' own pages as summarized on our roaster profiles, checked 2026-09-27.