The fourth largest city in the country and the 10th largest port in the world, Houston also ranks as the U.S. metropolitan market with the most equitable distribution of America’s major racial and ethnic groups. The diversity is on full display in the city’s more than 10,000 restaurants featuring 70-plus cuisines. The home of fajitas and the source of prized ingredients from the gulf, Houston claims some of the country’s best Mexican and Vietnamese eateries. Currently, the area is also experiencing both a barbecue and Tex-Mex renaissance.

A big Texas welcome is typical in restaurants and shops of every stripe. At Killen’s Barbecue, for example, long weekend lines are made more tolerable thanks to free samples of both food and beer.

Strong on Chinese, Mexican and Vietnamese restaurants — a reflection of the city’s diverse demographics — Houston has a relaxed style that might explain fewer examples of upscale French and Italian experiences.

If it’s short on cookbook stores, Houston features markets whose inventory whisks consumers to Asia, Mexico and the Middle East. Especially impressive are the sprawling Hong Kong Food Market for produce and Phoenicia Specialty Foods for ingredients from around the globe. On the rise: bakeries, including Fluff Bake Bar, home of cakes in a cup.

Cooks have the benefit of first-rate citrus — grapefruit, Meyer lemons, satsumas — and a sea of possibilities from the gulf, including snapper, grouper, shrimp, oysters and crab. (Texas produces almost 70 percent of the nation’s shrimp.) The Port of Houston, ranked first in U.S. imports and export tonnage, means easy access to goods from around the world.

Fajitas, a signature Tex-Mex staple, were created here. A more modern expression of tradition, say insiders, is Vietnamese pho. And the whole world can get around Asian-Cajun seafood boils.

Few markets enjoy the camaraderie found in Houston’s food scene. The leader of the pack is Underbelly, which distributes a list of dozens of the chef’s favorite places to eat with diners’ checks. Sugar & Rice, an impressive food quarterly edited by author David Leftwich, tells stories about the Gulf Coast — its ingredients, history and people — that typically aren’t covered by mainstream media. The Gulf Coast Food Program at the University of Houston promotes the scholarly study of food in the region via documentary films, oral histories and public lectures.

Among chefs garnering the most attention are Chris Shepherd, whose Underbelly roams the world for inspiration; Justin Yu, a wonderman with vegetables at Oxheart; and Hugo Ortega, whose Caracol shows off Mexico’s coastal cuisine. Both the barbecue and Tex-Mex scenes are redefining themselves. Count on the sides at Gatlin’s BBQ to be as mouth-watering as the meats, and watch for a margarita cart to roll through the upscale Añejo restaurant.

Pride and barbecue

For all its culinary progress, Houston hasn’t ditched tradition. Barbecue remains a mainstay and has friends in high places, including the newspaper of record, which employs a columnist dedicated to the subject. His name is J.C. Reid, and his weekly column in the Chronicle, launched last year, testifies to the allure of meat cooked low and slow, and not just locally. “What fascinates me is how other cultures assimilate something I’ve known my whole life,” says the native of Beaumont, Tex,, where the barbecue style mixes Southern traditions with Cajun influences: primarily pork with tomato-based sauces ratcheted up with cayenne and garlic.

Three years ago, Reid co-founded the Houston Barbecue Festival as a way to honor a dozen (mostly) mom-and-pops, an afternoon event that brought out 1,200 attendees. Last year, 25 vendors showed up for a crowd that had swelled to 2,500.

Who better to show a visitor the ropes than Reid, and where better to stain our fingers than at Killen’s Barbecue, in the nearby city of Pearland? Launched two years ago as a pop-up within Killen’s Steakhouse, the bricks-and-mortar extension is a prime example of what has been hailed as a “barbecue renaissance” in Texas.

Behind the counter is owner Ronnie Killen, a trained chef who sees barbecue as more than smoked meat. “I try to be about the whole experience, from start to finish,” says the 1999 graduate of Le Cordon Bleu in London, who employs an unusually large staff of about 20 and is known for passing out Lone Star beer to folks waiting in line on weekends. (Texans are nothing if not generous.) The line snaking away from the door makes sense after eating here. Killen buys some of the best meat possible (purveyors include Strube Ranch in East Texas and Allen Brothers in Chicago) and insists that the sides and sweets be on par with all that they flank.

Before we eat, I ask Reid, joined by festival co-founder Michael Fulmer, to give me the skinny on how to peg a model barbecue spot from a corner-cutter.

“You want to smell the smoke,” says Fulmer. The type of wood “is a preference thing”; mesquite can be a hassle, but post oak burns well. Killen tells me he uses different wood for different meats: pecan for beef, for instance, and hickory for pork.

Next, Fulmer says, “walk in back” of the business, to look at the process. Killen’s uses four different kinds of smokers, the main one being an all-wood-burning Oyler. Reid likes to scope out a barbecue joint’s dumpster area for tossed packaging to “see where the brisket comes from” — all-natural Creekstone Farms Master Chef, the expert notes approvingly of one of Killen’s choices. When we reach the meat counter, Reid directs my attention to brisket that unfolds like an accordion after it’s sliced and held up — the all-important “jiggle factor.”

We make our way to a table where my guides spread out butcher paper and we dig into an indoor picnic of brisket, ribs, bone-in pork belly, creamed corn, smoky baked beans, bread pudding and — anyone got an extra stomach to spare? Each bite packs Texas pride. Pork sausage — punched up with pepper, garlic and mustard seeds — comes with an audible snap. Brisket benefits from a crust of Malabar peppercorns, ground fresh every week, while the gloss and savor on the beef ribs comes by way of fish sauce, lemon juice and brown sugar. Collard greens balance the tang of apple cider vinegar with pork jus; berry cobbler relies on Granny Smith apples for welcome tartness and texture.

No one eating at Killen’s could say barbecue isn’t an art.

Pulling up a chair to chat, the chef ticks off some of the variables that influence barbecue, among them “wind, temperature, wood, humidity.” Reflecting on his résumé, he says, “Fine dining is easy compared to this.”

The warm fall afternoon prompts Reid to weigh in with another indicator of a good barbecue operation, an ingredient Killen’s also claims: “AC. It’s huge!”