A Transportation Security Administration officer we’ll call Pat told me very politely, even gently: “Sir, you’re not going to be able to carry this vanilla on the plane with you.” She cradled it in her hands as if it might start crying soon. The jar was securely bound in the bubble-wrap manner of breakable duty-free, though you could still see the little gingham cloth that covered the lid like a Betsy Ross sleeping cap.

Pat is one of 50,000 such officers screening some 2 million travelers a day, according to the TSA website, for purposes of airport security. The agency was formed two months after 9/11 as a branch of the United States Department of Transportation. Since 2003, it has operated under the jurisdiction of the Department of Homeland Security.

Pat told me that I would have to check the vanilla to get it on board, and that I could do it for free and “then come back through this checkpoint and I’ll move you through.”

I hesitated. My family stood off to the side, reassembling themselves for the Dallas-to-Tulsa leg. I explained the predicament to my missus. “OK,” she said with a smile. “We’ll wait here.”

I buckled my belt and laced my shoes, peeled peso coins off the bottom of one of those ubiquitous gray trays, and otherwise reclaimed the contents of my pockets. Pat looked at me and quietly said, “And next time, sir, you can leave your wedding band on.”

• • •

“I’m going back to the Motherland,” a Veracruz friend of mine told me once before a trip. “Want me to bring anything back? And don’t say vanilla.”

Totonacs harvested vanilla near Veracruz in the 15th century, then gave it to the fiery Aztecs to keep them appeased. Moctezuma liked it in his chocolatl, a cup of which he gave to Hernán Cortés, thinking he was the snake-bird god Quetzalcoatl come to reclaim the kingdom. Thus began the reign of Spain.

Vanilla is native to Mexico, a fruit of the only extant fruiting orchid. Only in Mexico are the blossoms naturally pollinated. Two other islands renowned for their hand-pollinated vanilla are Tahiti, in the Society Islands, and Réunion, a French possession off the coast of Madagascar. Two islands 9,000 miles apart, but straddling the 20th parallel—a great looping vanilla vine.

A lot of the so-called Réunion vanilla is grown on the northeast coast of neighboring Madagascar. Réunion was once called Ile de Bourbon, and so its vanilla is often referred to as Bourbon vanilla, not because it will get you drunk—it will, as real vanilla extract must contain, by law, at least 35 percent alcohol—but because the island was established by the French House of Bourbon.

After saffron, which must also be harvested by hand, vanilla is the most expensive spice. A good way to stretch a vanilla bean is to sink it in a pound of sugar, which after a while becomes vanilla-perfumed. A cheap way to stretch it is to add coumarin, a food additive banned in the United States in 1954 that’s still legal in Mexico.

• • •

The Mexican mercado where I buy camarones con cabeza and chicharones the size of elephant ears stocks, by my count, seven vanilla-looking products:

• Danncy, from the border town of Nuevo Laredo. “Danncy Pure Vanilla!” the website screams, where you can buy a case of 12 one-liter bottles for $46. Here, at $2.99 for 12 ounces, how “pure” can it be? The exclamation point is a dead giveaway.

• Goya Pure Vanilla Extract, at $3.99 an ounce, is more like it. Ingredients include “vanilla bean extractives” and 35-percent alcohol, an FDA purity requirement.

• Adams Extract, out of Austin, Texas, is a comparable $3.49 for an ounce and a half. But, it’s also flavored with vanillin (a naturally occurring compound of the plant, but also the name of a synthetic substitute, a liquid-waste byproduct of wood pulp) and colored with caramel. And, in spite of the tagline—“Adams Best. Twice as Strong”—it includes a thin 12 percent alcohol.

• Mi Huerta costs $2.29 for eight ounces and includes not only the suspect vanillin but also corn syrup.

• Molina ($3.29 for 8.3 ounces) at least calls itself a “Mexican Vanilla Blend.”

• Mamá Lycha ($3.29 for 16 ounces) seems more known for its vanilla cookies.

• La Vencedora looks the most like the Mexican vanilla Americans tend to favor, in its 31-ounce bottle decorated in gold medal prizes. It’s a mere $8.29, includes the vanillin, and contains but 12 percent alcohol.

Across town, and by comparison, the Nielsen-Massey Mexican Pure Vanilla Extract carried by Williams-Sonoma is $12.95 for a four-ounce bottle. There is a restraint in the packaging that makes it look more like vanilla and less like snake oil.

• • •

I arrived at the ticket counter to find no one in line, a strange enough sight in Tulsa, let alone DFW. I walked up and told the attendant my dilemma. She said that’s easy, but I’ll need a box: “Have you got a box?”

I said no and she said, “I’ll go see if I can find something.” She was gone 10 minutes, an afterlife in airport time. I grew anxious. Nobody was behind me in line, which made me nervous. I texted my wife to commiserate. She informed me that I had some wiggle room, as our departure had been delayed. I began to wonder if the attendant got sucked into the baggage conveyor belt when, voilà, she appeared with a box that seemed tailor-made for one of those long-necked reposado tequila bottles. It swallowed my little jug of vanilla.

“I don’t suppose you have any tape?” I asked. “And some paper?”

“Oh, sure, and you can pack it with this,” she said, handing me several sheets of blank newsprint. “So where are you going?”

“Tulsa,” I said, stuffing the box with wadded up paper.

She looked up from her monitor. “Then it’ll be $25 to check it, I’m afraid.”

“Oh, I was told it would be free.”

“It usually is, from most airports,” she said, “but Cancún is not one of those, airports. I’m sorry.”

I balked at a $25 excise on a $6 item whose authenticity was surely lacking. “That’s OK,” I said. The box was now an albatross whose neck I wanted to wring. “What should I do with this?”

She said she’d throw it away for me. I left it on the counter and steeled myself for another security check. Somewhere, in the bowels of DFW, I pictured a room full of duty-free liquor and fragrance, enough to stock, well, a duty-free shop.

• • •

The producer Nielsen-Massey has noted some 300 distinctive flavor compounds present in vanilla beans. None of them are among the synonyms associated with vanilla as listed in Merriam-Webster: beige, characterless, faceless, featureless, indistinctive, neutral, noncommittal, nondescript.

Vanilla is the most popular flavor in the world, the milquetoast of flavor profiles. Vanilla is protean, like a politician. It derives its immense popularity from its presumed neutrality.

The word derives from the Spanish vainilla, a diminutive of vaina, from the Latin vagina. In vanilla, the pliant sheath that opens to reveal a collection of ripe seeds.

In English, Merriam-Webster’s definition begins to set the table for the irony of vanilla, by definition a contradiction in terms:

• Having the flavor of vanilla

• Not having any special features or qualities

The full definition affords no relief:

1 Flavored with vanilla

2 Lacking distinction : plain, ordinary, conventional

Vanilla sex, as defined by the British Medical Journal, is any homosexual activity “that does not extend beyond affection, mutual masturbation, and oral and anal sex.” A gift card called Vanilla Visa proclaims, “One card. A million options.”

• • •

As I stood there with my shoes unlaced, I cursed my choice and duty-free in general. At Cancún International Airport, the duty-free shop greets you after you clear customs, sits within plain sight of the food court, and leads unmolested to the boarding gates. While it’s possible to check an item there, it’s not required and hardly intuitive. There is no “Don’t forget to check your duty-free hooch before you board” warning.

In Dallas, this loophole became my runaround. The TSA officer in charge of scanning passports had closed his second-class station and moved over to handle Business and Priority, abandoning the bulk of us. I don’t mind having to sit in the back of the airbus, but, when it comes to transportation security, aren’t we all equally suspect?

A sweet old couple in front of me loitered with their luggage, chatted too familiarly with a TSA traffic cop, like those people airing their laundry at the post office counter. Once my passport was scanned by the rubber-gloved hand of God, I slipped in line past the couple, who’d stopped to inventory their coat pockets.

Tedium aside, a new campaign appears to be underway in airports: service with a smile. It’s such a balancing act, that of security and courtesy. Whom would you suspect: the nice gentleman in the suit and unbuttoned collar who smells like Issey Miyake and assists a mother of three with her carry-on, or the couple in flip-flops berating each other for taking so long at the Starbucks counter?

Everyone, and no one.

• • •

I made it through security, again, and was loose somewhere in the grid of Dallas-Fort Worth International. Could anybody have foreseen a metropolis in north-central Texas? In hindsight, it seems destined to have become precisely what it is, one of the great distributors of humanity on the planet. “Airport police issue 12,000 traffic citations each year,” reads a newspaper report noting the 40th anniversary of DFW. “Airport detectives handle about 1,600 more serious crimes. Nearly 40,000 parking spaces are expected to generate $125 million in revenue…” The city within.

Forty years ago it was three runways, three terminals, and 66 gates. Now, it’s a hub, and a series of hubs, a honeycomb of coming and going spun by a climate-controlled tube called Skylink. In the middle of it sits a Hyatt that caters to salesmen and those laid over and whoever else gets stuck here.

Waiting for the digital voice of assurance to announce my gate, I scanned the Tarrant, Denton, and Dallas horizons. Several faux skylines clumped here and there. Big D loomed vaguely in the distance, a purple haze, a shadow of the real deal.

• • •

Chocolate’s reigning queen of connoisseurship is a 99-pound Parisian named Chloé Doutre-Roussel. When she was a chocolate buyer for Fortnum & Mason in London, she ate a pound of chocolate a day, a couple of boxes of which she kept beneath her bed. She’s traveled the chocolate belt in search of hidden riches.

Chloé’s vanilla equivalent is Patricia Rain. In her blog post “How I Became the Vanilla Queen,” Rain tells a story of survival, her own from breast cancer and that of the Mexican vanilla growers she’d rallied behind in her golden years. The keepers of the true faith. She prays for the vanilla men and women, and they for her.

Many have sworn allegiance to chocolate, but who would champion vanilla?