Water Temperature and Why It Matters
It's a common refrain: The perfect water temperature for brewing coffee is 195-205 degrees Fahrenheit. But why is this? In most brewing guides it will explain that this is the ideal temperature for "proper extraction," but what IS extraction? What are we even talking about!? Read on to learn more about water temps and coffee extraction!
So what do we mean when we say extraction? Extractions is simply the act of dissolving the solubles from the coffee grounds and bonding them with the water. One way to conceptualize this is to imagine water saturating your grounds during brewing, and that water pulling the good parts out of the grounds as it passes through them. The filter then stops the leftover gritty, grimy bits of the coffee. The stuff that ends up in your cup is water bonded with the flavorful, caffeinated parts of the coffee.
But what does temperature really have to do with this?
Coffee extraction, or brewing, is a chemical process. Things like grind fineness, amount, and water temp matter because chemistry happens in the brewer as you brew! On a simple level, things like grind fineness can make it easier for the water molecules to bond with the coffee grounds. Temperature plays into this as well! In truth, you can actually brew coffee with water of any temperature, the problem is control. Cold water extracts very slowly, which is why cold brew can take many hours to properly, well, brew. On the flip-side, near boiling water extracts coffee VERY quickly. Since varying flow rate is even more challenging than controlling temperature, and since temperature is constant, it's the variable that is easiest to control.
For all of these reasons, we've determined a 195-205 degree Fahrenheit range as being the best for coffee. The remaining question, of course, is where exactly should you set your kettle? 204? 196? This is going to come down to the roast and brew method more than anything. Some brew methods, like AeroPress, work even better below 195, but for simplicity's sake we'll stick to the 195-205 range. In general, presses work best lower in the range, as the pressure of the press aids in extraction. On the opposite side is pourover, which is usually better brewed around or above 200 degrees Fahrenheit. That said, all of this really comes down to the taste of the roast.
More bitter roasts tend to want cooler water, closer to 195. On the other hand, if your coffee turns out sour, try brewing a little hotter to aid in proper extraction.
Either way, there's plenty of room for experimentation! The most important thing is using an adjustable kettle like the Fellow Stagg or the Bonavita Variable kettle. Armed with these tools and the knowledge above, you'll be ready to really experiment with water temp!