A few miles outside of Arandas in the mountains of Jalisco, Mexico, the paved roads turn to rutted red clay, and fields of lemons and garbanzos give way to plantations growing a single crop: blue agave. The spiky, sun-scorched plants spread out across the valleys and up the ridges, shimmering like a spectacular blue-green ocean.

Most of the world's tequila is made within a half-day's drive of here – high in the mountains outside of Guadalajara, in a part of Mexico not many Americans visit, an agricultural heartland home to a fast-growing, multimillion-dollar global export still produced in much the same way it has been for almost 400 years.

I've come out here to discover how tequila is made – and to find the best. "Tequila is simple to make, technically," says Marko Karakasevic, a 13th-generation master distiller who recently expanded his family's California vodka and whiskey business to include a small-batch tequila called Charbay. "But it's complicated to make really good tequila. It's like wine – it's complex."

As the sun sets over the Sierra Madre mountains, Karakasevic draws a bottle of Charbay Blanco that's been hiding under a sweatshirt in the console of his Dodge SUV, takes a pull, then passes it to me. The taste is smooth and earthy up front, sweet going down, with hints of fresh honey and chamomile – nothing like the gasoline-charged shots that gave you a three-day hangover in college. "Tequila's gotten a bad rap," he says. "The good stuff is magical."

Until relatively recently, it was difficult to find high-end artisanal tequila in the U.S. But since Patrón opened the luxury-export market in the 1990s, dozens of smaller, hand-crafted brands have started to find their way onto the shelves of upscale U.S. bars and restaurants, and even casual drinkers are discovering that – contrary to queasy spring-break memories – good tequila is not only extremely drinkable; it's capable of carrying the kind of refined and nuanced subtleties that have long been associated with fine wines.

"People are starting to break through the old stereotypes," says Mark Alberto, owner of the Sayulita Fish Taco Tequila Bar, a six-stool joint in the surf town of Sayulita, north of Puerto Vallarta. Alberto stocks almost 400 varieties behind his varnished-wood bar – everything from a plastic water bottle decorated with a hand-drawn skull and crossbones to an ornate ceramic bottle of Clase Azul Ultra Extra Añejo, a rare aged tequila that's locked in its own iron case and goes for $420 a glass. But Alberto prefers to share the simple, well-crafted brands he loves most – lesser-known names like Centinela, Siete Leguas, Tesoro. "No salt, no lime, no cigars here!" he announces. "I want you to taste the tequila."

Ninety-eight percent of all tequila is made in Jalisco, in two distinct regions: the arid, volcanic Lowlands around the sleepy town of Tequila, population 25,000, where old-school giants José Cuervo, Herradura, and Sauza are based; and the Highlands region to the northeast, where the altitude keeps the agaves smaller, with more concentrated flavors, which many connoisseurs believe makes the best tequila.

With four or five days and a rental car, you can tour spectacular countryside and visit dozens of distilleries – from huge modern places like Cuervo to new boutique producers like Casa Noble, where you can rent a deluxe bungalow overlooking the agave plantation. The tequila region is old-world, rural, and religious, with most towns built around shady squares dominated by massive cathedrals. Driving into any of these places, you'll see men selling plastic jugs of moonshine by the side of the road. (The Consejo Regulador del Tequila, which regulates the tequila industry, advises wariness of street vendors. "You don't know what you will get," says CRT spokesperson Monica Campos. "Tequila – or something that might make you crazy.")

Lodging in the area is no-frills and cheap, and the food is exceptional, eaten casually at open-air taco stands (which specialize in delicate cuts of beef and spit-roasted al pastor pork with pineapple) and roadside joints like the incredible Carnitas Jaime in Arandas, where farmers feast on all varieties of fried pork, along with hundreds of local tequilas.

One thing you learn after a few nights of tasting tequila in the local bars is that while no one agrees on which one is best, all good tequila must follow a few simple rules. First, it must taste like the plant it comes from. You wouldn't want your vodka to taste like potatoes, but tequila must taste like agave, full of earth, spice, fruit, herbs.

There are two basic types of tequila: On the lower end are mixed tequilas like Cuervo Gold that contain a minimum of 51 percent agave (the rest of the ingredients can be additives like sugar or caramel); on the higher end are tequilas made from 100 percent agave (the bottle must be labeled this way) and water, nothing else.

Once tequila has been distilled, it is either bottled almost immediately for blanco (silver), or aged in whiskey or wine barrels: up to a year for reposado; up to three years for añejo; more than three years for extra añejo. The longer the tequila stays in the barrel, the more it mellows and takes on the flavors of the wood – and the more expensive it is. Americans schooled on cask-aged spirits like scotch generally assume that older is better, but unlike with whiskey, aging tequila often just masks the flavor. "Blanco is the pure form," says Fernando Gonzalez de Anda, owner of Siete Leguas, one of the finest Highlands makers. "Reposados and añejos can hide flaws. With blanco, there's nowhere to hide."

The process of making tequila involves only a few steps, but each one can be performed in different ways that radically affect the taste. After the agave plants are ripe, they can be roasted slowly for days in a brick oven or cooked in a high-pressure autoclave for as little as 45 minutes; they can be mashed using a large wheel-like stone called a tahona or by automated sugar-cane shredders; they can be fermented in wooden barrels or steel vats. I met one tequilero at a tiny company called Gran Jubileo who plays classical music in the barrel rooms where the liquor ages once it's distilled. "I believe the vibrations of the music give the tequila depth and character," he says.

One of my favorite Lowlands tequilas, Fortaleza, was created by Guillermo Erickson Sauza, the fifth-generation heir to the Sauza tequila empire, who advanced his family's art by reinstating near-primitive production techniques. At a time when multinational corporations were taking over the tequila industry and automated machinery was changing the way the spirit was made, Sauza reopened one of his grandfather's old factories in downtown Tequila, refurbished the original equipment, and began producing a rustic, bold-flavored tequila using only estate-grown agave in the same exacting style as his grandfather a century earlier.

If Fortaleza is about old-fashioned style, Casa Noble, located in the hills across town, blends tradition and technology into one of the finest new-school tequilas today. Growing all its own agave on a lush 22-acre plantation, Casa Noble mashes the plants with an electric shredder designed by co-owner Carlos Hernandez Ramos and distills the liquor three times (most tequila is distilled twice) for smoothness and clarity.

Every tequilero I met has his own secrets, and third-generation Highlands maker Carlos Camarena, who along with his brother Felipe runs the companies El Tesoro and Tapatio, has more than most. Trim, handsome, and much younger-looking than his 72 years, Camarena led me on a detailed tour of his pristine El Tesoro factory, accompanied by his Siberian Husky, Maya – named for Mayahuel, the goddess of agave.

"Tequila is a very different animal from any other liquor," he says, leaning against his Ford pickup in front of the distillery. "It takes seven or eight years to grow the agave – so you have a big investment before you've even started." Many distilleries use enzymes like ammonia and sulfites to speed up the fermentation, but for masters like Camarena, it's important not to rush the process.

"There is no single way to make great tequila," he adds. "All great tequila is made in a very personal way, and that is what's special about this drink. If it's done right, all that personality goes right in the bottle."