Should I let water sit before brewing?

There is a common myth in the coffee world that letting boiled water sit for a few minutes—or letting it 'rest'—improves the flavor by allowing chemicals like chlorine to evaporate. While it is true that chlorine is volatile, the amount that escapes into the air during a short rest is minimal. More importantly, the act of letting water sit causes it to lose heat rapidly, which can lead to under-extraction and a sour, thin-tasting cup.

Coffee extraction is highly dependent on temperature. If your water drops below the ideal range (typically 195°F to 205°F) before it hits the coffee grounds, it will fail to extract the full spectrum of flavors, particularly the sugars and complex aromatics. By the time you wait for the water to 'rest,' you have likely moved outside of the optimal temperature window, resulting in a brew that lacks body and sweetness.

If you are concerned about the taste of chlorine in your water, the solution is not to let it sit, but to filter it. A simple activated carbon filter will remove chlorine far more effectively than letting a kettle sit on the counter. By using filtered water, you eliminate the need to worry about chemical off-flavors and can focus entirely on hitting your target brewing temperature.

In practice, consistency is the key to great coffee. You want to be able to repeat your brewing process every morning with the same variables. Using fresh, filtered water and brewing as soon as it reaches the correct temperature ensures that your extraction remains consistent. Don't let your water sit; instead, invest in a good filter and a reliable kettle, and you will find that your coffee is much more balanced and enjoyable.