Loris Foalp doesn’t care if you’ve never heard of him. He’d be happy if you thought he didn’t exist. All that matters to him is his gravy.

Foalp operates Washington’s hippest food truck. It serves one thing only: gravy. No mashed potatoes. No stuffing. No biscuits. Just gravy, doled out in lidless plastic foam cups: $5 for a small, $7 for a large.

It takes me a while to find Foalp, who has been getting approving buzz on such local foodie blogs as Tongue Lashings and the District Masticator. When I finally do track him down, parked on E Street behind the FBI building, he doesn’t feel like chatting.

“I let my gravy do the talking,” says the 20-something Foalp.

He’s quite a sight: bearded, amply pierced and with arms that are veritable canvases. They’re tattooed with antique cooking utensils: measuring cups, sauce pans, spatulas, a pepper mill, a melon baller, a mandoline. Peeking out from the neck of his indie band T-shirt is a tattoo of a sausage grinder. Inked across the knuckles of his hands is MORE SALT.

A line of customers stretches from the Gravy Train, which is what Foalp calls his truck. The truck is as distinctive as Foalp, modeled as it is after Raymond Loewy’s art deco streamline locomotive.

You never know where the Gravy Train will pop up. Unlike other D.C. food truck operators, Foalp doesn’t advertise his location. He doesn’t have a Facebook page or a Twitter account. He tends to stay away from typical food truck haunts such as Farragut Square and L’Enfant Plaza. He drives where his mood takes him, with his massive pots of gravy bubbling and burbling in the back, casting a warm and hearty smell spell over the blue highways.

Wherever he parks the truck, he is quickly discovered, and his fans disseminate his whereabouts via social media.

The customers I saw certainly seemed to go away happy, cupping their crucibles of brown liquid as if they contained a magical elixir.

When the last pot was emptied, Washington’s gravy king finally agreed to an interview.

Foalp says he grew up around here. He went to an Ivy League college but became bored and left in his sophomore year to go traveling, first to Spain, where he worked in the kitchen of a highly-rated Barcelona chef.

“I spent a whole year doing nothing but cutting the last two inches off stalks of asparagus,” Foalp says. “And the next year deveining shrimp.”

With those two essential skills in hand, Foalp hitchhiked to Asia, where he learned how to fashion radish roses. He spent nine months in Ethiopia learning how to properly pronounce the word “injera.” (“It turns out I’d been saying it right all along,” he says ruefully.) Constantly on the move, Foalp became famous in the Seoul street food scene, setting up his own bibimbap cart with nothing but a block of paraffin, a Bic lighter and a knife made by sharpening a metric ruler.

Always he was learning.

“I realized that what matters is the essence,” he says. “Simplicity. Fusion cuisine is a dead end.”

So: the Gravy Train. A different gravy every day. Beef gravy, chicken gravy, giblet gravy, sausage gravy, cream gravy, red eye gravy . . .

For red-eye gravy, Foalp has been known to use actual red eyes: the eyeballs of albino rabbits and goats. This sort of boundary pushing has endeared him to the extreme food crowd, people for whom Korean tacos and caramelized anchovies served with a reduction of Heath bar and grappa are passé, who are constantly searching for the Next Big Thing and are delighted when the Next Big Thing turns out to be a heartland staple meticulously prepared by a tattooed, pierced, college dropout.

Aficionados say one of Foalp’s most sublime offerings is his jus. Just jus. Rather than sell it in white plastic foam cups, he ladles it into clear plastic tumblers so the light can penetrate and twinkle like the stained glass in a cathedral, a Notre Dame of meat drippings.

But, really, what can you do with a cup of gravy?

“All sorts of things,” says this Shostakovich of sauce, this ladle-laureate, this Johnny Gravyseed. “You can drizzle it on mashed potatoes or on meatloaf.”

True, I say, but you don’t sell those things. And what if the nearest food truck doesn’t happen to be a mashed-potato van or a meatloaf-mobile? What if it’s a cupcake truck or a popcorn truck?

“I’ve seen people put it on cupcakes,” Foalp says. “Just scrape the icing off and pour it on. And I’m surprised no one’s put it on popcorn before. That sounds pretty good, actually.”

There’s something about the way Loris Foalp says it that almost makes me believe in him.