August 24, 2016, is the day Starbucks was forever ruined for me. That’s when I met Chris Chacko. The 48-year-old owner of Sparrow Coffee Roastery had arranged a tasting for me at the company’s West Loop headquarters. On a waist-high wood table in Sparrow’s warehouse-slash-roastery-slash-office stood an array of coffee-making paraphernalia: French presses, hourglass-shaped Chemex brewers, porcelain Hario V60s that fit snugly over a mug and brew one filtered cup at a time. Chacko, wearing jeans and a trilby hat, was standing on the other side of the table and speaking in measured tones—a professor delivering a lecture to yet another misshapen freshman mind.

“What I’m going to show you today is what I do for every chef that comes in here,” he said before proceeding to prepare the first sample, using one of the V60s.

Chacko handed me a cup of coffee made from beans grown on a 3,000-foot-high plateau in Brazil, and I took a sip. The flavor was rich and round and redolent of cocoa nibs. Very good, but not wildly out of the ordinary.

The second cup contained an Ethiopian varietal made from heirloom beans. Chacko introduced this coffee by saying, “This is equivalent to the food at a three-Michelin-star restaurant.” I fought the urge to roll my eyes. Then I took a sip.

Chacko smiled and said, “Blueberries. Very clean, very precise.”

Yep. The flavor was unmistakable.

“But now add some sugar. Notice how the flavor shifts.” He passed me a wooden bowl of raw turbinado sugar. I mixed in a couple of spoonfuls.

I sipped, and Chacko smiled once more. “Citrus.”

Right again. Suddenly all I could taste was the sweet-tart pucker of oranges, so intense I could almost feel my tooth enamel deteriorating. Then he passed me a carton of Kemps half-and-half. I swirled in a hearty glug.

“Now what do you taste?” he asked. I sipped and my eyes widened.

“Blueberries,” I said. “Again.”

“Exactly.” The half-and-half had coated my palate, Chacko explained, stamping out the acidity, and the exotic blueberry flavor of those Ethiopian beans was all that remained.

“We look at coffee as the leaves of a fall tree,” he said. “All those colors are there throughout the tree’s life, but you only see them in the fall, when the chlorophyll dies and the green goes away. What we’re doing is taking the green away so you can see the beauty.”

And just like that, I was a believer.

Chris Chacko thinks about coffee differently from the rest of us. He sees it as others see wine: something rarefied and complex, an elixir to be tasted and savored and understood for the way it interacts with the elements of a meal. He is Chicago’s high priest of coffee, and he counts among his acolytes the best and most innovative restaurateurs in town, from Paul Kahan at the Publican to the doughnut wizards at Glazed and Infused. His espresso is served at Monteverde; his coffee spikes a dessert at 42 Grams. Four of Chicago’s 10 best new restaurants, including top spot Oriole, use Sparrow coffee. Chacko told me that when Michael Muser of Grace—speaking of three Michelin stars—did the same tasting I did, he laughed in disbelief and then asked for a contract then and there.

But not just anyone can serve Chacko’s coffee. He has turned down roughly half the restaurateurs who have approached him—not because his eight-employee company can’t handle the volume but because Chacko doesn’t think highly enough of the food at those establishments. For those who make the cut, Chacko goes to great lengths to please. Every one of the roughly 250 restaurants that Sparrow does business with (almost all of which are in and around Chicago, with a few out in California) gets its own unique coffee, custom-roasted by Chacko and calibrated to pair harmoniously with the restaurant’s culinary approach.

The single-origin Mexican coffee at Rick Bayless’s West Loop restaurant Leña Brava is a dark roast from which Chacko has vaporized all the smoke, a byproduct of roasting that often imparts a woodsy flavor; when you add a little cream and sugar, the brew blossoms into an approximation of cinnamon-spiked Mexican hot chocolate. Thomas Lents, the former chef at River North’s Sixteen, favored the blueberry-forward Ethiopian coffee for one of his high-concept tasting menus. Abraham Conlon of Fat Rice in Logan Square chose a wickedly robust blend that could stand up to a palate numbed by the tingly hot Sichuan peppercorns flavoring many of his dishes.

As of now, restaurants are the only places where you can taste Chacko’s coffee, though the Sparrow website and a few of Chacko’s favorite places—Mexican darling Quiote and sunny fish-curing café Snaggletooth, for instance—sell 12-ounce bags. This summer, Sparrow’s first coffeehouse will open in Naperville; there are plans for a second one in the city to follow.

Several restaurateurs I talked to described occasionally bewildering encounters with Chacko. When Snaggletooth opened, Chacko would pop by regularly and ask owner Bill Montagne to make him a coffee; then he’d offer advice unbidden. “I was self-conscious about it—I’m a chef, not a barista,” says Montagne. “But he’d give me pointers: pour this way; you’re doing this wrong. And he’d tell me not just how to do it right, but how he could tell, just from tasting, what I was doing wrong.” One day Chacko came in, tried Snaggletooth’s nitro cold brew—a kegged coffee that pours like a beer—and then texted a day later to say that he’d been thinking about it and that Montagne needed to up the pressure on the keg.

Chacko, who emigrated from India with his family when he was 7, knows of what he speaks. He has been roasting coffee beans since he was 18, when he built his own roaster in his parents’ Elmhurst garage using plans he found in a library book. His fascination with coffee was born of deprivation. His mother was allergic to the stuff—“She’d break out in hives if she drank it,” he says—so it was never around the house.

Chacko, who claims coffee has never affected his sleep, lives alone in a River North apartment and begins his day at 5:30 a.m. by grabbing his laptop to pull up the automated reports generated by Sparrow’s $200,000 Loring roasting machine, which captures and records data points for airflow, temperature, and four other parameters at six-second intervals. He saves these reports indefinitely, referring to them during tastings to pinpoint tiny fluctuations that might explain a particular nuance in strength or flavor.

Case in point: A few years back, he noticed a subtle black pepper note in a wild Ethiopian brew. It’s a note you rarely detect in coffee. He couldn’t figure out how it had gotten there and wanted to be able to replicate it in the rest of the roasts he did with those particular beans. On the report, he noticed a variation in temperature, just 10 seconds long—likely due to a minor adjustment he’d made at the time but hadn’t noted. He programmed his roaster to repeat that change. Boom. Black pepper in every batch.

Chacko is all about precision. He evaluates every brew he makes using the 100-point scoring system adopted by the Specialty Coffee Association, grading cups on factors such as aroma and acidity and making sure his employees come to the exact same score as he has at the end of a tasting.

His dedication leaves room for little else. He used to build and fly kites and go running in his spare time. Now, though, when he isn’t working, he is mostly dining out. Which is also work. He visits at least one restaurant a day, vetting potential clients and making pairing notes for existing ones. (His single-day record: a tasting menu at Grace, followed by another at Oriole, followed by a burger at the Loyalist.)

Chacko’s epicurean zeal can verge on the monomaniacal. On several occasions during my visits with him, I tried to steer the conversation to topics other than coffee and cuisine, to no avail. The exchange would simply sputter out, and before I realized it, we’d be back to, say, the merits of a particular Michelin-starred restaurant.

When it comes to evaluating the quality of a restaurant, Chacko grades meals the way he does coffee, using a 100-point scale, in this case one he created. An 86 is equivalent to one Michelin star, an 88 to two stars, a 91 or higher to three.

After dining, he often takes to Twitter to share his thoughts—both good (“Table Donkey Stick has evolved to a level of intrigue & sophistication w/subtle French Canadian influences that elevate throughout”) and bad (“Kitsune is plagued with executional errors throughout & has no resemblance whatsoever to the food of a Michelin starred chef”).

Over dinner recently at the nouveau steakhouse Maple & Ash in the Gold Coast, Chacko explained his philosophy to me. “You cannot have emotion involved,” he said emphatically as rib eyes were placed before us. “Subjectivity is an excuse people make to mitigate errors. Because our evaluations of things have to be calibrated, or things fall apart.” He gestured at his plate. “What we look for in steak, first, is technique. Is this cooked properly? How’s the temperature? Then we cut into it. What kind of meat is it? Can you tell that it’s prime?” He took a bite and chewed. “Then you look for nuances—here I get some herbaceousness—but the key defining factor is, is it memorable?”

Even a dish’s memorability, though, can be objectively evaluated in Chacko’s world. He took another bite of the steak, pondered for a moment, and then handed down his verdict. “This dish is at least an 85, maybe even an 86. Because if I were to come here tomorrow and taste this, I’d be able to tell it was [executive chef] Danny Grant’s version of steak, with all the fire elements. It may need a sauce, though, and for it to be an 88, it would need a creative aspect other than simply technique.”

Chacko believes in flavor as science, not art, something to be technically executed in point-by-point increments. Which, as I told him, happens to be the exact opposite of how I think about food. For me, and the average diner, eating is about sensual pleasure; assigning a score, as if you’re some kind of culinary gymnastics judge, takes all the fun out of it. But while I’m searching for emotional resonance, Chacko is seeking some kind of objective perfection.

In Chacko’s utopia, every restaurant critic’s reviews would include numerical scores, and every course of a meal—not dessert only—would be paired with coffee. He doesn’t want to just echo the flavors you’ve already tasted in a meal; he wants you to have the perfect coffee for that roast chicken dish as you eat it. “Coffee’s the most complex beverage known to humanity,” he says. “It has twice as many flavor-producing ingredients as red wine.” A chocolaty Brazilian coffee can work well with hamburgers or chicken, he explains, while something like that fruity Ethiopian brew might go well with fish and lightly blanched vegetables.

For now, though, Chacko must content himself with finding the perfect coffee for the culmination of a meal, the consummate coda to a particular progression of dishes and flavors, since none of Sparrow’s clients are proposing coffee in the middle of dinner—yet.

“It was like, ‘pfft, no contest,’ ” says David Posey of the decision to serve Sparrow coffee at Elske, the Scandinavian-inflected restaurant he opened last year on Randolph Street with his wife, Anna. The three of us are standing in Sparrow’s warehouse for a tasting. Like me, David and Anna have been here before. Between their first Sparrow tasting and this one, they visited a few other roasters and quickly came to the conclusion that Sparrow was in a different league. Today, Chacko is determined to get the Poseys to decide on a custom blend for Elske.

In their first session, they gravitated toward both an earthy Sumatran roast and an acidic Colombian varietal—“completely opposite coffees,” Chacko says with a hint of exasperation. He now has two new ones in mind. The first is a Brazilian Catuai with light hints of chocolate and lots of acidity—ideal for Anna’s creamy, floral-tinged desserts. He’d sampled it a few days prior and had been blown away by its delicate balance of flavors and aromas, but he’s still waiting on a new shipment. For now, he’ll have the Poseys taste a similar Brazilian coffee alongside a Yemeni one and the Colombian and Sumatran ones they liked last time.

Chacko delivers his professorial preamble: “What I’m going to do is cup these for you like we would on a farm, deciding whether to order the beans.”

He has placed four small white ceramic bowls in a circle on the wood table—one for each of the four varietals. Each bowl contains exactly 12.5 grams of ground beans and will be filled with just enough hot water to result in a 21.25 percent extraction (basically, the amount of flavor the beans are allowed to release). This simple, unfiltered method, says Chacko, gives the most direct taste of the bean, because a coffee’s flavor can change depending on how it’s brewed. Coffee made in a French press, for example, tends to have more body because more coffee solids make it into the cup than with a paper-filtered brew.

Chacko adds the hot water. Grounds rise to the top of each bowl, forming a crust. We wait precisely four minutes, and then Chacko hands the Poseys spoons and instructs the couple to dip them in, stir three times counterclockwise, and sniff. We wait eight minutes more, to let the coffee cool to optimum tasting temperature.

Anna starts with the Brazilian Catuai. “I would say it’s chocolaty?” A hint of uncertainty creeps into her voice. Chacko nods.

The Yemeni coffee is as delicate as a fine tea. David is enthralled by a lingering impression of berries in the Colombian. The Sumatran offers hints of coriander and baking spices. But when it comes to which will pair best with Elske’s cuisine, the Poseys seem unable to decide.

So Chacko makes a few decisions for them. “The Sumatran you tasted is great, but I think it’s too abrasive to go with David’s food,” he says. “It’s a steak, lamb, red meat sort of coffee.” Also out is the Colombian, which Chacko worries might clash too much with Anna’s dairy-rich desserts.

Now Chacko adds an equal amount of the Brazilian and the Colombian to a Chemex brewer and pulls two cups. “It’s so drinkable,” Anna says. Chacko makes a few more blends, but after two hours of sniffing and sipping, the Poseys leave still undecided. Two months later, they settle on a Colombian blend.

I’ve sampled it—with Elske’s rye bread pudding topped with quince sorbet—and it had what I’d call a fudgy aroma, and tasted a little bit fruity. I ask Chacko later what I should have been detecting.

“Cocoa nib. Raspberry,” he says. Close enough.

I do know for certain that it fit the meal perfectly.