So you’ve finally upgraded the water you’re using for brewing your coffee. Now, it’s time to dial in the perfect temperature that your precious H2O should be when it makes contact with your fresh coffee.
Ideal Temp. The Specialty Coffee Association suggests that water for coffee should be at 200°F ± 5 when your brew first begins. If it’s too hot or boiling (212°F), your coffee will over-extract and produce a bitter taste. Too cold, and your coffee will under-extract and end up flat.
Kettles & Temperature Reading. Coffee snobs like us invest in electric gooseneck kettles that reach manually set temperatures and hold them there during a brew, allowing for maximum control and consistency. Bonavita makes great ones for around $50, or you can pick up a stove top gooseneck kettle for $30. Goosneck’s are great because of the ability to control the flow of water with minimal splashing; helpful with any manual brewing style (pour-over, Chemex, Aeropress, etc.).
When using any stovetop kettle, we strongly suggest using a quickread electric thermometer for measuring the temperature (a digital meat thermometer works well). Dip it into your kettle as the water heats up and aim for between 200-204°F. Once you turn off your stove and begin your brew, the water will begin to cool, so aim for the higher end of the suggested temperature range. Another option is to heat the water to boiling, measuring the temperature as it cools. After several times doing this, you’ll have a sense of how many minutes your water takes to cool from 212°F to 205°F.
Note. If you don’t have an electric kettle or thermometer, let your water boil on the stove and once it starts whistling, turn it off, move it to a cool burner, and let it sit for about 2 minutes. There’s far less accuracy, but letting it sit can ensure you’re not scorching your coffee with boiling water without worrying it will be too cool (it will take more than 2 minutes to fall below 195°F).
Altitude. Remember science! The boiling point of water decreases by roughly 1°F every 500 feet due to lower atmospheric pressure, so keep that in mind for mountain high brewing. As an example, if you live in Denver your water will start boiling around 203°F or so (which, presumably, you already know). The lowered boiling point of your water shouldn’t affect the brew, as long as the temperature still falls within the SCA approved range noted above.
FYI. All of this guidance emphasizes manual brewing, but if you're using a countertop drip coffee maker, there’s a host of considerations to be mindful of. We’ll open that can of worms in a later post.