Chris Frankel at the Underbelly bar with (l to r) his White Portonic, Quinquina and Americano cocktails made from his small-batch aromatized wines. Photo by Alison Cook

I was a bit startled by my first sip of Underbelly bartender Chris Frankel's Americano. It's one of the liquor-free cocktails he's dreamed up using his own house-brewed aromatized wines — a trade term for wine flavored with various botanical ingredients.

The amber liquid looked so innocent in its slender tulip glass. I hadn't been expecting the deep, headspinning vortex of burnished bittersweetness that pulled me in and kept me interested, picking out traces of Asian spice: ajwain, fenugreek, fennel, star anise. Its base wine was dry, tart Torrontes (an Argentinian white), and the addition of gentian root, a classic bittering agent, defined the blend as an Americano.

But what an Americano: altogether more complex and specific to Houston — and to Underbelly chef Chris Shepherd's bold, ethnically influenced food — than a commercial variety would be. I love and use Cocchi Americano, the brand most easily purchased in Houston, but I can't imagine it standing up to such dishes as Shepherd's voluptuous free-form terrine of pig's head, the satiny slices zapped with pungent mustard and crowned with a rich five-minute egg. Let alone a skilletful of General Tso's meatballs, as fat and tender as Shanghainese Lion's Heads.

That's the whole point of this unusual cocktail (or is it "cocktail"?) program at a restaurant that is only licensed to sell wine and beer. With the menu geared to what's local and house-made, went the reasoning, why not do our own aperitif aromatized wines, too? Frankel models them only loosely on the classics, riffing at will to find his own fine balances. Instead of acting in the supporting parts that they fill at most cocktail bars, for a change these aromatized wines get a starring role.

The Quinquina cocktail at Underbelly,. Photo by Alison Cook

How does he concoct them? "Basically I make a tea with a little wine and other ingredients," says Frankel. Make that a lot of other ingredients, many of them hard to come by, because "you can't just go to the store and get gentian root," as he puts it wryly. He burned his first batch and learned to watch them closely. He has to strain the mixture four or five times to filter out the finely powdered quinine bark and the other botanicals. Mostly, though, says Frankel, "it's just a matter of balancing so many ingredients."

By a process of trial and error, Frankel has already mastered two of the three major kinds of aromatized wines, the Americano and a delicate Quinquina, defined by the quinine (powdered chinchona bark) that bitters it. He's working on a house version of Vermouth, traditionally bittered with wormwood, but that's taking longer. "Vermouth recipe 4, Frankel 0," he Tweeted mournfully last week when the latest batch failed to meet with his approval.

I have a feeling he'll get there. Slight and intense, with a shy demeanor and a quick darting glance, Frankel is all purpose when it comes to food and drink. At Anvil Bar & Refuge, where I first encountered him mixing cocktails (and where he still pulls shifts when he's not at Underbelly), he worked quietly and intently, with a scholarly precision that hinted at his Princeton education, and a keen interest in Asian flavorings that hinted at his half-Korean roots.

I'll never forget sampling my first Frankel cocktail, dancing with blackberry fruit and the Indian spices that are becoming his trademark. It was sweet, even a little darkly jammy, qualities I often flee in a drink. But it was so meticulously balanced that I ended up liking it a lot. "I like sweet, that's my palate," says Frankel. "But I back it up."

Frankel has brought that same deft calibration to his aromatized wines. The pink-flushed Quinquina (pronounced ken-keena) is based on a rose of garnacha (the Spanish grenache), and its distinctive shiver of quinine edges the soft flavors of vanilla, lavender, cacao bean and plum that Frankel adds. It's refreshing and gentle without cloying, thanks to that quinine astringency, and it seems made for a Houston summer.

Underbelly's house-bottled version of a White Portonic cocktail by Chris Frankel. Photo by Alison Cook

Underbelly serves the Quinquina (and its other aromatised wines and house-bottled punches and phosphates) straight up, as either an aperitif or a dessert drink, without any additions or further tinkering.

I couldn't help wondering how the Quinquina would taste as part of a champagne cocktail, though, and I ended up mixing my own: ordering a glass of sparkling wine and pouring in Quinquina to taste. It was terrific. I wish they'd mix one for me — and perhaps one day they will — but I'm willing to take matters into my own hands.

There's more, and it comes in fetching little bottles. Last year Frankel was inspired by Jeffery Morgenthaler, bar manager of the wonderful Clyde Common in Portland, to begin experimenting with house-bottled carbonated drinks. One of the results is Underbelly's White Port and house-made tonic blend, an homage to the Portuguese summer drink known as a Portonic.

Again, the distinctive quinine edge of the citrus-laced tonic gives the blend its particular tingly thrill, and Frankel's addition of spices from Goa, Portugal's former colony in India, gives it his (and Underbelly's) stamp. I kept tasting something beneath the coriander, fenugreek and ajwain, and Frankel told me it was amchoor, the tart mango powder, "for a little earthy note."

Frankel plans on updating the house tonic recipe seasonally, to highlight changing local citrus and the like. He's already introducing off-menu specials like a bottled sparkling cocktail of Gruner Veltliner and sweet cider; or a Tropical Peychaud's Punch flavored with Peychaud's bitters, dry apple cider, vanilla, grapefruit and pinot noir. Just ask what's available.

Off-the-menu special: Frankel's experimental-stage tribute to Pakola, the Pakistani soft drink. Photo by Alison Cook

There's something of the mad scientist to Frankel: I don't think he could stop tinkering and reformulating even if he wanted to. He let me sample his tribute to Pakola, the bright green Pakistani soft drink, which sat in its tumbler shimmering an unearthly shade of emerald. The color came from food coloring, he told me cheerfully, but he's working on finding some natural coloring agents for the brew, which consists of Riesling, Madeira, and soda flavored with rosewater, vanilla and cardamom.

The satisfying thing about this unusual bar program is how well it fits with Underbelly's excellent wine program run by Matthew Pridgen, and how well it dovetails with chef Chris Shepherd's voraciously multicultural tastes.

Frankel is just as prone to epic ethnic restaurant crawls as Shepherd is, and even more apt to document them on his Twitter feed (his handle is @csfrankel), where his forays through Houston's wide world of Asian restaurants are the stuff of local social-media legend.

His affect couldn't be more different from the gregarious, bear-hug-dispensing Shepherd, but drinking Frankel's unique aromatized wines at Underbelly's hospitable bar, I've come to realize how much the two men are alike, and what a good thing that is.

To catch Frankel in his new habitat, try coming during his Wednesday and Thursday evening shifts, when he's tending bar from 6 or 7 p.m. until closing.

The wine bar is open daily except Sunday, from 11 a.m — 2 a.m. During restaurant hours it serves the entire menu, which is to say from 11 a.m. —3 p.m. weekdays, and from 5 p.m. —11 p.m. Monday — Saturday. In the afternoons, from 3 p.m. — 5 p.m., and again at night from 11 p.m. , special bar/late-night menus go into effect.

Underbelly, 1100 Westheimer Rd., 713-528-9800.)