Water—it’s 90 to 95 percent of our beer. Or, maybe it’s only 80 percent if you’re a fermentation masochist. Regardless, it’s the vast majority of our favorite beverage, yet it’s the least talked about in the homebrewing world.
Much of homebrewing is the sort of stuff you can casually wave a hand at, like we can with malt, hops, and yeast. With those ingredients, you can usually predict what will happen with a few simple algebra equations. You can often get great results with ballpark guestimates and simple rules of thumb.
Not so with water. It’s understandable—it’s chemistry, and it doesn’t like to be ignored. The margins between great and awful can be measured in grams. Water chemistry is finicky. The sensory impacts are subtle and, based on a few factors, shift like a mirage.