As interest in specialty coffee continues its meteoric rise, so too has the number of shops opening in big cities and small towns around the world. Here in the United States, coffee bars have been experimenting for years with different ways to enhance their espresso service for their customers, or at the very least distinguish it from that of their newfound competition. From reclaimed wood trays that visually titillate to snifter glasses and champagne flutes that enhance the olfactory experience, more and more shops are implementing an approach that goes beyond the traditional demitasse-and-saucer-only preparation.

We know of coffee bars choosing to augment the café experience by pairing espresso with a rogues gallery of other imbibeables: hazelnut milk, carbonated black tea, all manner of macaroons and macarons, and even cappuccino and milk have been served alongside espresso in shops across the United States. What you pair with your espresso says as much about your coffee bar these days as the espresso itself.

Still, sometimes a few ounces of bubbles are sufficient to create a memorable coffee experience. This is perhaps most true in Texas, where our espressos are often served with a sidecar of the aggressively effervescent mineral water known as Topo Chico. Sourced from a spring at the base of Cerro del Topo Chico in Monterrey, Mexico, this carbonated wonder is sold only in Mexico and the United States, and with all due respect to the other states that get to occasionally quaff from this mythical elixir, serving Topo Chico alongside espresso is a uniquely Texan proposition. In as much as Topo is American, it is Texan. Just one sip from this fizzy hombre paired with an espresso shot, and you've geolocated yourself within the borders of The Cult of Topo Chico.

Topo Chico and espresso is a Texas thing–by which I mean it's delicious, and proof of a loving and merciful God. With that in mind, let me present to you a Topo tour of Texas coffee. Not every shop is included, of course, because we'd be touring 'til the end of time then. What I've got is four shops with distinct identities, advancing Texas coffee culture forward in unique ways, and pairing their espressos a bubbly liquid that one shop owner calls “tiny happy fairies dancing on your tongue with razor blades.”

Avoca Coffee

Our tour begins with a traditional Topo pairing at Avoca Coffee Roasters. Set in Fort Worth, Dallas’s western sister city, Avoca was one of the first specialty shops in any part of the now-blooming DFW Metroplex; owner and mad scientist Garold LaRue opened his shop/roastery in early 2011, when specialty coffee was much more difficult to find within the city limits. There were a few shops, but often drink quality would vary wildly from barista to barista. LaRue was one of the first to put a premium on both drink quality and uniformity between visits.

This idea of quality and reliability manifests itself in Avoca’s tools of the trade. Behind the bar, Avoca uses a three-group La Marzocco Linea, an industry workhorse, along with three black Mazzer Major E espresso grinders. But the Linea is not without a few modifications; a PID, custom steamwands, and dispersion screens on each group head have been added, all made to allow for more control, leading to a more easily repeatable product.

Given LaRue’s straightforward, product-over-showmanship approach, it should come as no surprise that Avoca’s espresso presentation is no-frills (kind of). Shots are served in white, NotNeutral porcelain demitasses with Gibraltar glasses of Topo Chico on the side. No serving trays, no miniature munchables. Just a well-pulled shot and an aggressive bubbly palate-cleanser.

Southside Espresso

Houston often gets overlooked as a coffee city, even by Texans. It’s a fairly insular scene and it’s not off of I-35, the highway running through Dallas, Waco, Austin, and San Antonio that is quickly becoming the state’s coffee corridor. But with Houston being home to green coffee importer InterAmerican Coffee, they have long been a player in the national coffee game, so it is unsurprising that there are quite a few quality shops. One such shop is Southside Espresso, and these guys go for the quality and quantity approach.

Since 2012, Southside has been serving coffee and craft beer (these guys know bubbles) to Houston denizens residing inside the highway loop known as Interstate 610. Offering guest roasters like Cuvee and Four Barrel along with their mainstay Fusion Beans, owner Sean Marshall’s roasting company, Southside, pulls their shots from a three-group La Marzocco Strada EP coupled with a Mazzer Robur E and a pair of Mazzer Kony E grinders. To complement their espresso, they serve a healthy portion of Topo Chico, like a full 6.5 ounce bottle healthy.

“We used to serve small glasses of Topo poured from large bottles, but halfway through the big bottle, it would lose some of its pop,” Marshall explained to me. “So now we just included a 6.5 ounce Topo Chico with every espresso. Same fizzy zing every time and super refreshing. A friend of mine said it was like tiny happy fairies dancing on your tongue with razor blades.”

Patika Coffee

No Texas coffee tour is complete without a stop in Austin, where the Topo flows like wine. The hardest part is picking just one shop. But there is one spot that is using the yellow-labeled elixir in inventive and refreshing ways, and it’s not a shop at all; setup in the heart of downtown Austin is the Patika Coffee trailer, and they are beating back the Texas heat with Topo Chico Italian sodas.

Working within a space as small as a trailer hasn’t kept Andy Wiggington and the crew at Patika from operating as a full service coffee destination. Using a Tardis-like architectural design, they have somehow found a way to house a two-group Synesso Cyncra and Anfim Caimano grinder to pull shots of their primary roaster Cuvee along with occasional guest roaster, Austin’s Flat Track. Despite spacial limitations, Patika still houses a full manual brew station; a Mahlkoënig Kenia serves as the grinder for the the French press and V60s on the brew bar.

But operating out of a trailer means being subject to the elements; there’s no air-conditioned building to give customers a brief respite from Austin summers. So Patika has to offer more creative reprieves from the heat. They do so by making Italian sodas using Topo Chico to offer to anyone not quite fanatical enough to drink hot coffee during the hotter summer days. They also serve Topo with their espresso for the coffee faithful that disregard the seasonal hindrances.

Davis Street Espresso

Our final stop is back where we began, in the DFW Metroplex. Set in Dallas’s Oak Cliff neighborhood, Davis Street Espresso is the storefront for Oak Cliff Coffee Roasters, and it is a gear geek’s dream. Their lab alone has enough cool toys (think HG One grinders, Speedster espresso machines, and GS/3s) to keep your inner coffee tech delighted for hours, but it pales in comparison to what they keep behind the bar. For their espresso program, Davis Street uses both a three-group Bosco lever machine and a two-group Kees Van Der Westen Spirit. A four-crucible Alpha Dominche Steampunk couples with a double-hoppered peach Mahlkonig EK43 to create Davis Street’s manual brew station.

But this is about espresso, and more importantly, about espresso and Topo Chico. Every espresso and “Van Buren”, what Davis Street calls their cortados, is served with a four ounce mason jar’s worth of refreshing Texas bubbles. And as you’ve no doubt noticed by now, the cult of Topo Chico produces a hefty amount of empty glass bottles. So what does Davis Street, an environmentally conscious shop that doesn’t even carry paper to-go cups (much to the chagrin of first-time visitors on the go), do with all this incredibly slow moving liquid? They use them to bottle their cold brew. By reusing the iconic yellow-labeled bottles, Davis Street is able to cut down on the waste created and ironically enough, create a coffee product for the to-go crowd.

So there you have it, four Texas coffee bars serving Topo Chico alongside espresso. There's dozens more to choose from, but this is where our tour trail ends for today. Here in Texas, our state motto is “Friendship,” our state mammal (small format) is the armadillo, and our state bubble water–hecho en Mexico and paired gloriously with espresso—is most assuredly Topo Chico.

Zac Cadwalader is a Sprudge.com staff writer based in Dallas. Read more Zac Cadwalader on Sprudge.