A Botanist's Take on What Makes Great Tequila

The author of The Drunken Botanist knows that everything begins with the careful cultivation of agave.

Amy Stewart is the author of The Drunken BotanistAmy Stewart, author of The Drunken Botanist, is pretty much the go-to expert on the plants that go into making alcoholic beverages. As she puts it, “Once spirits go into the bottle, that’s where my expertise ends. After the plants come out of the ground, lots of people know what they’re doing.”

But before that point, Stewart is a goddess among plants. With tequila, mezcal, raicilla, and other spirits, that means looking to agave. “Tequila [must be] made from a particular species of agave, agave tequilana,” she says. “I think that well over 100 different species of agave have been identified by botanists. Occasionally someone will call it a cactus. It’s not a cactus, it’s an entirely separate kind of plant.”

The type of agave that goes into making tequila is much more specific. “Within a species, you can have what’s called a cultivar," Stewart says. These variants are bred for particular traits. “They can still breed with one another, and are still biologically quite similar,” Stewart says. “The Mexican regulations specified that [tequila] had to be made from a specific cultivar of agave tequilana called Weber Blue.”

Jimadores in a tractor in the agave field Jimadores carefully select the finest Highlands Weber blue agave when making tequila.

The difficulties of growing agave

From an agricultural standpoint, this is bad news. “When you specify that the only thing that can go in the bottle is one particular cultivar, you really limit the ability of farmers, of growers, to be able to innovate, improve, and deal with real environmental issues like disease control, water issues, and the ability to withstand extreme temperatures,” she says.

“This is the particular case with agave. The concerns were that [it’s] increasingly susceptible to diseases and pests,” she continues. “Bugs can evolve much faster than humans can. Whatever pests are attacking Weber Blue can evolve in a pretty short period of time, and we don't have the chemicals or organic controls to kill them off.”

For plants that take a decade to mature enough to be harvested, this is a big problem. But if the regulation isn’t changed to allow for development of new cultivars, there may be other ways to combat environmental threats.

“It’s important to look outside your own industry and say, 'What’s happening with wine growers? Sugar cane growers? Apple growers?' Let’s look outside for a solution to this problem because someone’s probably figured it out for their crop,” she says. “Wine growers have really looked at biodiversity in terms of how they farm so that it’s not a monoculture, but is broken up by wide areas, a kind of agricultural buffer zone of wild plants.”

That "zone" can serve several purposes, like specifically attracting pollinators and bugs that will eat a plant’s natural predators. But the impact of this buffer of wild plants goes below the surface, too. “Sometimes, these can help with things like irrigation or soil health,” Stewart says. “The thing is, you have to take some land out of production to create these areas, and there has to be an incentive to do that.”

An agave field in Jalisco, MX. Jimadors harvest an agave field in Jalisco, MX.

Learning from other plants

Though some producers wild-harvest their agave, there’s a downside to that as well. “I was sitting in a talk at Tales several years ago and heard people say that they wild-harvest [agave], and there’s so much out there that we’re never going to reach the end of it — that we couldn’t possibly harvest them all because there’s so much,” she says.

As someone who lives on land that used to hold an old-growth redwood forest, in a house built from redwood trees, she knows firsthand the dangers of overestimating a wild population. “Ninety-five percent of the old-growth redwood forests on this planet are gone,” she says. “How can you not learn from every other wild population of plants in the world?”

Though Stewart is the first to make it clear that plants that have been fermented and distilled aren’t her specialty, she still enjoys partaking of drinks made from them. But her proclivities for tequila are as specific as her botanical research. “I don’t like margaritas or sours or anything like that,” she says. “I think that a lot of lime or lemon juice in a cocktail is overwhelming and just kills the drink. I like tequila drinks that are made with something else.”

“When I go to taste really good agave spirits, I don’t want them in a cocktail,” she says. “Many of these really fine spirits are meant to just be enjoyed neat.”

Clair McLafferty is a writer and bartender based in Birmingham, AL. She is the author of The Classic & Craft Cocktail Recipe Book, and collects (and drinks) whisk(e)y for fun.

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