Water flows through a paper filter and ground coffee, then drips into the bottom chamber

A Chemex brews coffee by pouring hot water over ground coffee held in a paper filter, letting gravity pull the water through the grounds and into a glass vessel below. The water extracts flavor from the coffee as it passes through, and the paper filter traps oils and fine particles, leaving behind a clean, bright cup. The whole process takes about 4 to 5 minutes from start to finish.

The Chemex looks like an hourglass made of glass, with a narrow waist in the middle. That waist is where the filter and coffee grounds sit. Hot water poured into the top chamber soaks the grounds, then drips down through the filter into the bottom chamber, where your finished coffee collects. You pour the brewed coffee directly from the Chemex into your cup.

Key Takeaways

  • A Chemex uses a paper filter thicker than standard coffee filters, which removes more oils and creates a cleaner taste than other brewing methods.
  • Water temperature should be between 195 and 205 degrees Fahrenheit; boiling water straight from the kettle is too hot and will scald the grounds.
  • The brewing time is roughly 4 to 5 minutes total, with the first 30 to 45 seconds spent "blooming" the grounds to release trapped carbon dioxide.
  • Chemex filters are folded into a cone shape and must be rinsed with hot water before use to remove paper dust and preheat the brewer.

The three parts: filter cone, glass vessel, and wooden collar

The Chemex has three main components. The glass hourglass vessel is the body—it holds both the grounds and the finished coffee. The paper filter cone sits in the narrow middle section and holds the ground coffee. The wooden collar and tie around the waist are purely decorative and help you grip the hot glass safely.

The glass is thick and heat-resistant, designed to withstand the temperature swings of hot water poured in and room-temperature air around it. The paper filter is the critical piece: Chemex filters are about 20 to 30 percent thicker than standard coffee filters, which means water passes through more slowly and the grounds stay in contact with the water longer. This longer contact time extracts more flavor.

Preparing the filter and rinsing out paper dust

Before you brew, you must fold and rinse the filter. Chemex filters come as flat, folded squares. Open one and fold it into a cone shape, with one layer on one side and three layers on the other. Place the cone in the top of the Chemex with the three-layer side facing the spout—this helps direct water flow.

Pour hot water (around 200 degrees Fahrenheit) through the empty filter to rinse away paper dust and preheat the glass. This step takes about 30 seconds. Discard the rinse water, then you are ready to add ground coffee. Skipping this step leaves a papery taste in your cup.

Grinding coffee and measuring the right amount

Grind your coffee to a medium consistency—similar to sea salt or coarse sand, not powder and not chunks. A Chemex brews best with a medium grind because the thick filter slows water flow; finer grounds would clog the filter and make the brew bitter, while coarser grounds would let water pass through too fast and under-extract.

Use a ratio of 1 part coffee to 16 parts water by weight. For example, 30 grams of ground coffee to 480 grams of water makes about 16 ounces of finished coffee (accounting for water absorbed by the grounds). If you do not have a scale, use 1 tablespoon of ground coffee per 5 ounces of water as a rough guide. Pour the ground coffee into the rinsed filter cone and level it gently with your finger.

The bloom phase: letting carbon dioxide escape

Pour just enough hot water to saturate the grounds—about twice the weight of the coffee. For 30 grams of coffee, pour about 60 grams (roughly 2 ounces) of water. The water should be between 195 and 205 degrees Fahrenheit; if your kettle just finished boiling, wait 30 seconds before pouring.

Let the water sit on the grounds for 30 to 45 seconds without pouring more. During this time, called the bloom, carbon dioxide trapped in the coffee grounds escapes. This allows water to penetrate the grounds more evenly in the next phase. You will see the grounds puff up slightly as gas is released. If you skip the bloom, the water will channel through the grounds unevenly and your coffee will taste weak or sour.

The main pour: adding water in a slow, steady stream

After the bloom, pour the remaining hot water in a slow, circular motion. Pour in stages rather than all at once—add water until the level reaches about an inch below the top of the filter cone, wait 20 to 30 seconds, then pour again. Repeat until you have added all the water. This staged pouring keeps the water level consistent and ensures even extraction.

The total brew time from the start of the bloom to the last drop falling into the bottom chamber should be 4 to 5 minutes. If it finishes much faster, your grind is too coarse or your water is too hot. If it takes longer than 6 minutes, your grind is too fine or your water is too cool. Adjust the grind size for your next brew based on how long it took.

Why the thick filter makes a difference in taste

The Chemex filter is the reason the brewer produces such a clean cup. Standard paper filters let some coffee oils and fine particles pass through, which adds body and richness but also leaves a slightly oily mouthfeel. The Chemex filter is so thick that it traps nearly all oils and sediment, leaving behind a bright, tea-like clarity.

This is not better or worse than other methods—it is a different taste. If you prefer a fuller-bodied cup with more oil and texture, a French press or pour-over with a standard filter might suit you better. But if you want to taste the subtle flavors in high-quality, single-origin coffee without the heaviness of oils, the Chemex is designed for that.

Frequently Asked Questions

Can I use a regular coffee filter in a Chemex?

No. Regular filters are too thin and will tear or let grounds slip through. Chemex filters are made specifically for the brewer's cone shape and thickness. You can order Chemex filters online or find them at most grocery stores near the coffee aisle.

What happens if my water is boiling hot when I pour it?

Boiling water (212 degrees Fahrenheit) will scald the coffee grounds and make the brew taste bitter and burnt. Wait 30 seconds after the kettle finishes boiling, or use a thermometer to check that the water is between 195 and 205 degrees before you pour.

Why is my Chemex coffee taking too long to brew?

The most common cause is a grind that is too fine. If the brew takes longer than 6 minutes, your grounds are probably powder-like and clogging the filter. Grind coarser next time. If the grind looks right, your water may be too cool—use hotter water, but not boiling.

Do I need a special kettle to brew Chemex coffee?

A gooseneck kettle (one with a thin, curved spout) makes it easier to pour slowly and control the water flow, which helps with even extraction. A regular kettle works, but you have to pour more carefully to avoid splashing or pouring too fast.

Can I make Chemex coffee ahead of time and reheat it?

You can, but the flavor will fade within a few hours. Brewed coffee tastes best within 30 minutes of brewing. If you need to reheat, use low heat or a microwave in short bursts to avoid scorching the coffee.