Despite my love for the stuff, I've never been able to make a perfect cup of coffee at home. There's a saying among Italian baristas that brewing quality espresso comes down to the four M’s: miscela (the bean blend), macinadosatore (the grinder), macchina (the machine), and mano (the hand of the brewer). No matter how much attention I've tried to pay to all four M's—or the number of videos, online forums, and articles I’ve consulted since the explosion of Third Wave resources hit the Web—I can't seem to get it right. A brand-new book from Lani Kingston, How to Make Coffee: The Science Behind the Bean (Abrams; $20), which aims to make better brewers out of its readers through a basic education in coffee’s chemistry, just may be my saving grace.
While Kingston—a journalist, pastry chef, and food studies expert—is neither a professional barista nor a chemist, she employed the help of both to write this book: World Champion Barista Matthew Perger and science manager Roger Cook from the Institute for Scientific Information on Coffee, to name a few. The no-frills hardback is a straightforward guide, elucidating coffee’s alchemic journey from the ground to your cup in plain prose and lo-tech visuals. A combination of the factual (touching on the species and anatomy of coffee plants, the chemistry of caffeine and its interactions with human physiology, the solubility of the bean’s various compounds) and the practical (how to roast, a discussion of the necessary gadgets, and step-by-step methods for how to brew), the book might not provide any groundbreaking discoveries for the coffee cognoscenti, but there’s certainly plenty here for the layman to chew on—she takes you through the four M's, and then some.
Take, for example, Kingston’s explanation of altitude’s effect on a bean’s taste: the higher the altitude, the longer the maturation period, the more complex sugar formations, and the deeper the flavor. Much like an oenophile interprets a bottle of wine, this simple principle turns cues posted on a bag of beans or chalkboard menu from inaccessible argot into practical knowledge: Thanks to her simple chart, now I know to expect more acidic, fruity, floral notes from Colombian or Ethiopian farms (set at heights of around 5,000 feet), and a smooth, sweet palate from the medium altitude locales of Brazil or Bourna (about 3,000 feet). “Single-origin” is no longer just a buzzword; If I understand where the crop comes from, now I can shop for the ones I like best.
None of this matters, however, without the proper equipment—another lesson I'm taking home from Kingston. Home brewers might as well trash their (expensive and) painstakingly selected coffee if they are going to use a shoddy grinder.
Since the size of the grounds determines taste—and each brewing method from French press to pour over requires its own particular bean-surface-area-to-hot-water-exposure ratio—having a precise grind size that’s uniform means a more balanced result. Since trading my Coffee-Mate for a Capresso burr grinder, I’ve had much more control over the flavors in my cup: If my brew’s too sour, that means the grounds were under-extracted, and using a finer grind will help slow down the process; if it’s too bitter, the grounds were over-extracted, and a coarser grind will help bring it back into balance.
Grind size is so important, in fact, that each size (more or less) has its own coffee-making machine, each boasting its own unique drinking experience: espresso requires a fine grind; a pour-over uses medium-fine; a Chemex, medium-coarse; and a French press, coarse. It’s enough to drive someone to spend not-so-small a fortune to try them all. Still, the claims are no nonsense, as Kingston explains in her section about the four main ways to brew: filter, boil, pressure, and steep. If flavor, mouthfeel, and aroma are all determined by the size of the coffee grounds, the amount of hot water they come in contact with, and the rate at which they mingle, the array of machines available to brewers has done wonders to highlight such alchemic minutia—and in such gorgeous objects, too. That’s why understanding what I like—or at least, what I’m in the mood for—might be the most valuable thing her machine breakdown taught me: I’ll never enjoy a crisp, clean pour-over if what I’m looking for is the full-bodied flavor of a French press.
All of Kingston’s lessons culminate in the last 30-odd pages, which are dedicated to a series of step-by-step brewing techniques. Many of these I tested to the T, treating them as a kind of theorem set up by the rest of the book’s proof: Having learned the intimacies of the bean, the grinder, and the machines, could I make a pot of French press—or a Chemex, a pour-over, or a macchinetta, for that matter—taste any better than I could before?
The short answer is yes. Though each explanation she offers might only be surface enough to satisfy a dilettante, How To Make Coffee’s 160-pages offer just enough wisdom for making informed choices—and not just how to do each step of the process, but why each one matters. It’s the difference between being precious and being precise; between experimenting madly and tweaking methodically. Whether you choose to follow Kingston’s brewing methods or someone else’s (not every direction in her book worked best for me), the connections she makes between chemical compound, technical process, and what ends up in your mug will stay with you, and help bring you closer to that elusive perfect cup.