For too long, American drinkers thought tequila and mezcal should only be chugged in frozen margaritas and in bottles filled with rotgut and a worm on spring break trips to Tijuana. Tequila and mezcal are finally having their moment, and achieving mainstream respectability in America—and around the world. But their newfound popularity is both a blessing and a curse. More fans of agave spirits means more attention on how they’re produced, and that means more attention on the economic and environmental issues associated with them. The next time you buy tequila or mezcal, there are some things you should keep in mind.

“Because tequila has now reached the whole global market, demand has increased. Increased demand requires more agave, faster,” says Cari Hah, the agave-loving manager at Los Angeles’ Big Bar. Hah has been a bartender for more than a decade and a member for the last five years of the Tequila Interchange Project, a non-profit organization dedicated to tequila education and advocacy for preserving traditional and sustainable production methods. “This is leading to a loss of traditional methods and a decrease in quality,” says Hah.

The problem starts in the agave fields. Tequila can be made from only one variety of agave — Blue Weber. Most producers transplant shoots, rather than allowing the agave to flower and be pollinated naturally (by bats!), which leads to fields of plants with identical DNA. “The problem is a lack of genetic diversity,” Hah says. “If that plant becomes susceptible to a pest or disease, it wipes out the entire crop at once.”

The Tequila Interchange Project is working on the problem, however: This year, it kicked off a pilot program to create a “Bat Friendly Tequila & Mezcal” label badge for brands that commit to natural pollination for at least 5 percent of their agave (look for it on bottles later next year.)

For the mezcal category especially, tremendous growth comes at a cost. The spirit was virtually unknown outside of Mexico barely 10 years ago, but is one of the trendiest today. “It’s a very exciting time because the knowledge about agave spirits is really growing, but that growth comes with its own challenges,” says Misty Kalkofen, east coast brand ambassador for Del Maguey, the first artisanal mezcal imported into the U.S. She gained fame running Boston cocktail bar Drink for many years, and has traveled extensively in Mexico visiting distilleries and agave growers.

“Agave can take anywhere from six to 35 years to reach maturity, and once you harvest it, it’s gone,” Kalkofen says. The wild-growing agave that goes into some of the most sought-after mezcals tends to take the longest to grow and is in the shortest supply. It’s also being harvested at an unsustainable rate. “Growth is possible, but it has to be gradual,” Kalkofen says. “We simply can’t drink spirits made from wild agave in the same volume as cultivated agave if we want to have any 10 or 20 years from now.” Thankfully, many mezcal brands are now participating in agave “reforestation” programs—but we wont see the results from these programs for years.

Plants are of course vital to agave spirits, but so are the people who harvest them, who are better known as jimadores. It’s the type of work that’s simultaneously strenuous, dangerous and precise, involving digging up the plant’s huge, heavy heart and shaving off the leaves and outer layers using a razor-sharp round tool called a coa. “Being a jimador used to be a craft, passed on from father to son. It was very romanticized,” Hah says. “But today, nobody wants to be a jimador anymore. It’s hard work, low pay and you get treated badly. They’re now basically day-laborers.” Even as the tequila and mezcal industries grow, wages for agricultural workers remain stagnant, and so workers are abandoning back-breaking agave-harvesting (and, indeed, from farm work in general).

Still, there are glimmers of hope here, as well. “Our industry has taken steps to educate people about how sugar cane cutters are treated and agave cutters are in a similar situation,” says Andrew Friedman, owner of Seattle’s Liberty Bar, which carries some 700 different spirits, more than 100 of them made from agave. He’s referring to a protest against Flor de Caña Rum by bartenders last year. Poor working conditions are causing deadly chronic kidney disease among sugar cane workers in Nicaragua, and the bar community focused international attention on the problem. The same is beginning to happen for agave: In response to queries from bartenders, a number of brands have taken pledges to pay above-market wages to their agave suppliers.

Even after harvest, there’s still more to worry about. There are lots of way to mechanize and improve yields over traditional methods, ranging from shredding instead of crushing the agave to steaming it in autoclaves instead of roasting over an open flame, to using a diffuser, a device that extracts sugars from raw agave, sometimes using nasty solvents including sulfuric acid. “There’s this push to be more efficient—you might be able to make more, but it won’t taste as good and won’t support the tradition,” Kalkofen says. “The things that we have to lose in the world of mezcal are more fundamental than other spirits—it’s a whole culture.”

To keep that culture alive, Friedman prides himself on supporting small, traditional producers and paying close attention to their production methods. “The growth in popularity of agave spirits is caused in no small part by bars like Liberty promoting them, so we’re sort of obligated to work to educate consumers,” he says. “You have to consider who you’re supporting and why. There are so many people with deep pockets buying agave for non-producer brands, which raises prices for small producers.”

On the other hand, smaller isn’t automatically better. “It’s very confusing and convoluted—some big companies are working toward being environmentally friendly, but some small ones aren’t.” Hah says. “A lot of the companies working to help are the same big companies that people vilify.”

So what’s an ethical tequila and mezcal drinker to do? Here are a few tips:

Mixto is a class of tequila that’s produced from a mix of agave and other, cheaper sources of sugar. If a distillery doesn’t use 100 percent agave, it’s also almost definitely not paying extra to ensure the agave it does use is sourced well. Thankfully, any brand that is made from 100 percent agave will say so proudly on the label.

Any medium or large city in America has at least one agave-focused bar with a library of dozens or hundreds of bottles. Find your local one, meet the agave expert on staff and strike up a conversation. Become a regular, and it’ll be like having your own personal agave guru. (Plus, tip well and you might get a free shot every once in a while.)

Start with the label: Some brands include production details right on the bottle, while others list it on their website. If you can’t find this info, it might be a red flag. “Transparency limits the opportunity for bad practices,” Kalkofen says. “If people are trying to hide things, they’re not going to be forthcoming about all the steps of the process.” Another resource is the NOM, an ID number issued to every tequila distillery in Mexico, which must be printed on every tequila label. Popular brand Patrón actually hosts a lookup tool that’ll let you see which distillery made any bottle, as well as what other brands are also made there. Want to go even deeper? Try a recent book called How the Gringos Stole Tequila, which covers the modern history of the spirit, while Divided Spirits is a deep-dive academic look at the politics of agave production.

When it comes down to it, the best way to preserve deliciously traditional agave spirits is to simply buy them, even when they cost more than other brands. Kalkofen puts it best: “It shouldn’t be $19 a bottle if everybody’s being compensated fairly for all the work involved.”

Hah’s top tequilas—for both flavor and sustainability—include Fortaleza, Casa Noble, Corralejo and Ocho. Friedman singles out Siembra Azul Tequila, La Niña del Mezcal and Mezcal Tosba, while he and Kalkofen both suggest Siete Leguas Tequila and Mezcal Vago, whose labels really stand out in the amount of production details they include.