Water and Kettles for Coffee
As coffee lovers, of course we obsess about the beans: Where they’re from, how they’re roasted, what flavor notes we expect to taste—the fun stuff, right? We hardly ever think about the true MVP of our morning pour-over ritual.
That’s right. Water.
If coffee is the heartthrob actor, think of water as the director: It’s water’s job to control the action and coax the best performance out of the talent. In fact, when it’s brewed properly, filter-brewed coffee is made up of more than 98% water. While we know that the coffee itself is more than just a pretty face, it is important to consider what goes on behind the scenes to get that perfect brew on the first take.
This post is going to explore the importance of water for coffee in a few ways, including explaining what water does during the extraction, what temperature range is ideal for most brewing, and how you can get the perfect pour by using the right kettle (or using the wrong kettle the right way).
Let’s dive in: The water’s fine!
How Much Do You Know about Your H20
Water is coffee’s best friend, its perfect complement. This is mostly due to the fact that water loves to dissolve things, and coffee loves to be dissolved! That’s essentially what extraction is: When water and ground coffee come in contact with one another, the water will immediately start to dissolve the various soluble compounds that exist in the coffee—including flavor and caffeine.
There are a couple of useful things to know about water so we can start to break down how to help it do this process more efficiently and deliciously.
First, temperature matters: For example, hot water dissolves things faster. Imagine trying to dissolve a package of granulated sugar in iced tea versus hot tea. Which one do the crystals disappear into sooner? (Sorry, iced tea—but that’s why we have simple syrup!) On the other hand, however, too-hot water can dissolve too much too quickly, leaving a bitter taste.
According to the folks who study this kind of thing, the exact brewing temperature might not be as pivotal as previously thought, but the recommended range for brewing hot coffee falls somewhere between 190°–205°F. (Ideally, you’ll start brewing when the water is on the hotter side, knowing that it will lose some heat over the length of the process.)
Temperature-controlled electric kettles can make this a cinch, but for stovetop kettles, many professionals recommend bringing fresh cold water up to a boil (212°F) before removing the heat and counting down for 30–60 seconds.
The other most significant thing to know about water and extraction is that just because you can see through it doesn’t mean it’s empty: All water except distilled water contains some amount of minerals like calcium, potassium, and magnesium. Water that has more dissolved calcium and magnesium is commonly called “hard,” while water with less is considered “soft.” While most municipalities in the United States have water systems that eliminate taste and odor from drinking water, the mineral content or hardness of water may impact the way it brews your coffee.
Imagine your brewing water is a subway car, and your ground coffee is someone waiting on the platform. If the car pulls up and it’s totally full of riders in all the seats and all the standing room, there’s nowhere to comfortably squeeze in, right? If it pulls up and there are a few passengers in it but some seats are still available, then it’s possible to get on and ride contentedly until your stop. However, if the car pulls up and is totally empty—and I say this to you as a former New Yorker—you almost always want to think twice about stepping onboard.
Water for coffee is kind of like that: You want it to have enough minerals to create a pleasant, balanced extraction, but you don’t want it to be too full to dissolve any coffee solubles, or too empty and dissolving far too many coffee solubles.
The Specialty Coffee Association has specific recommendations for water standards, if you want to get really geeky, but for most places in the United States, tap water that doesn’t have a taste or odor of its own is generally fine to use. A standard charcoal filter like a Britta filter is a great extra precaution, if you like. You can also go full specialty and order water-customization kits for brewing—after all, we are asking you to take water seriously.
Consider the Kettle
Now that we’ve had a primer about water, we need something to heat and pour it into our coffee: For most pour-over people, that means a kettle that does double-duty, either with an electric heating element inside or that can sit on a stovetop or induction burner.
Before you go kettle shopping, it’s important to consider your priorities. For some folks, cost is number one; for others, controlling the flow rate as they pour their water. Maybe you need one that has a built-in thermometer, or one that can be programmed to hold a batch of water at a certain temperature (in case you forget and walk away from your brew, like I often do).
For control, a gooseneck-shaped spout is the professionals’ favorite: It allows the user to modulate the volume of the pour, which can be especially helpful for brewing methods that call for a gentle and continuous flow, like V60s, or precise pulses, like the Kalita Wave. Brewers or techniques that call for a broader pour, such as some folks advocate in a Chemex, require less of that fine control, so a bigger and shorter spout like one on a typical teapot will do just fine. You can even make them work for your more finicky brewers by making sure that your kettle is up to its maximum fill line (which can cut back on agitation inside the bowl of the kettle) and pouring more slowly.
When it comes to temperature, there are a few different options: Electric models that will heat up to a boil and then shut off automatically, electric ones those that will heat up and hold water at a specific temperature, and kettles that will need an external heat source like a stovetop. (Note that some coffee kettles are used for pouring only, not heating: Be sure you check the instructions first.)
One of the prettiest and most sought-after electric kettle is the Stagg EKG Electric model with variable temperature control, which costs about $150 from Fellow Products. Hario’s V60 Buono Power Kettle is a classic favorite that is available for under $90, and old reliable Bonavita’s variable-temperature gooseneck kettle can be scooped for under $70.
I love stovetop kettles that have thermometers in the lid, which can be very helpful. OXO and Fellow Products both make very good models that are under $100.
The good news is you don’t need a fancy kettle to do a fancy job: While coffee-centric designs like gooseneck spouts are fantastic for control and precision, any standard tea kettle will do the trick if you know how to use it—and now you do!
The Last Drop
From now on, I hope you consider the humble pitcher of water as your greatest ally in the ongoing search for that perfect cup of coffee. It’s as important to coffee as jelly is to peanut better, or pepper is to salt, or your Ebb filter is to your favorite brewer: Heat it up, brew with it, say a little “thank you” over it in the morning—and don’t forget to drink eight glasses of the stuff without coffee every day, too.
ABOUT THE AUTHOR
Ever Meister is a coffee professional, journalist, and educator who has worked in the specialty coffee industry for 20 years, doing everything from making and serving espresso to selling green coffee to conducting training sessions and writing marketing strategies. Meister is also the author of New York City Coffee: A Caffeinated History (The History Press, 2017).