It is important that the coffee be ground medium-course with a quality burr (rather than blade) grinder. By grinding the coffee this way, you are allowing for a more even extraction resulting in a fuller bodied and more nuanced cup. Blade grinders chop the coffee rather than grinding it, resulting in uneven and unpredictable particle size. This results in uneven extraction, leading to coffee with increased bitterness which is less true to the flavor profile of the coffee. In addition, the lack of uniformity in particle size results in inconsistent results from cup to cup.
Place and Rinse the Filter
Place the folded chemex filter inside the cone with the multiple folds toward the spout. Run hot water through the filter to rinse out any residual paper flavor and preheat the brewer. Allow the water to drain out completely before pouring it out of the brewer using the pouring channel. Do your best to keep the filter sealed against the walls of the brewer.
We recommend 42 grams (1.5 oz or about six rounded tablespoons) of fresh ground coffee to make 20 oz of coffee.
You should bring the water just to a boil (electric kettles are great at this). For 20 oz. of brewed coffee you will want to use quite a bit more hot water total for the three pours. First, pour just enough into the cone so that it saturates the grounds and very little is dripping into the brewer. The key is to saturate all the grounds evenly by moving the stream around as you pour.
First Brewing Pour
After about 30 seconds it is time to pour more water. Pour at an even rate in a spiral and/or back-and-forth pattern in order to break down the bloom and saturate all grounds evenly. Raise the water level up to about a 1/4 inch below the rim of the brewer. The color of the surface should be even with as few dark or blond spots as possible.
Second Brewing Pour
Once you can see about an inch of dry coffee, it is time to pour more water. Pour first around the rim to re-submerge the dry grounds, then continue at an even rate in a spiral and/or back-and-forth pattern. Raise the water level up to the rim of the brewer. The color of the surface should still be even with as few dark or blond spots as possible.
Pull Your Filter
Once you have 20 oz. of brewed coffee in the vessel, quickly move the filter to your sink where it will drain completely.