Walters Sports Bar is a gleaming new pub just blocks from the largest stadium in Washington, D.C. The decor is industrial chic — exposed ducts and poured concrete floors — and it's spacious enough to accommodate the enormous throngs of elated fans who crowded in after the Washington Nationals' recent World Series win.

On a recent night, the bar was quieter. Still, customer after customer strode up to a stainless steel wall lined with beer taps to insert a card, touch a screen and pour a glass of self-serve beer.

No waitstaff. No waiting.

"This is my first time doing a beer wall!" says one patron, Chris Porcaro, over a yeasty IPA. "I've been to many sports bars, but never a beer-wall sports bar."

The shiny beer wall allows customers to choose from 23 different varieties of beer — or "24 if you count Bud Light," says owner Jeremy Gifford. Pour-your-own beer isn't just a novelty, Gifford says; the idea is to cut down on waiting for alcohol (which means selling more of it) and freeing up bartenders to make cocktails.

Laws regulating this technology vary from state to state. At Walters, the beer wall cuts customers off after they pour 32 ounces — the equivalent of two pints. For more, they must get approved by staff. ("We make sure you still got your pants on and everyone's doing OK," Gifford says.)

Pour-your-own technology has been featured in bars and restaurants for years, but its appeal has never been more obvious to owners staring at balance sheets that include astronomical rents in desirable locations and new mandatory minimum wage increases in 18 states this year.

"Labor is one of the largest costs in running a restaurant," Gifford says. "As it should be, right? We are in the service business and there needs to be an interaction."

Burly and bearded, Gifford is direct about his financial realities. His monthly rent at Walters costs him close to $30,000, he says. He employs about 24 people there. The beer wall set him back about $100,000, but he believes it will eventually pay for itself.

"If you have 50 self-serve taps, then you essentially have 50 employees you don't have to pay to service your customer," says Josh Goodman, who runs a company called PourMyBeer that sells this technology.

According to Goodman and others in the industry, self-serve taps are exploding in popularity. Back in 2015, Goodman says his company sold fewer than 200 taps. But over the past five years, he says it has sold more than 5,000.

Business doubled in 2017 at a similar company called iPourIt, says its vice president, Darren Nicholson. And last year, he says, it grew by a whopping 70%.

"When I entered the industry back in early 2016, there were probably only 80 locations in the U.S. [that sold self-serve beer]," Nicholson says. "There's currently about 400 in the U.S."

That may not seem like a large number, he says, but it's a 400% increase. Plus, Nicholson says, the technology allows Big Data to pull up a bar stool.

"It's all anonymized," he says. "But I can tell you, in a region, what 40-year-old-plus women prefer, just based on the demographics we collect from that region."

PourMyBeer's electronic taps do the same thing, says Josh Goodman: "The big initiative now is to get them all communicating to one centralized mothership dataset, so then we're gathering really unique information about products being dispensed."

It's not just beer. Self-serve wine bars are popping up around the country, observes Andrew Adams of the Wine Analytics Report, an industry monthly. He says that because staff needn't open just one bottle to serve a glass, the technology can reduce waste. And when it comes to cocktails, automated self-serve taps pour exactly the same drink every time.

Josh Goodman says PourMyBeer is working with Whole Foods, the U.S. military and even companies that do not serve alcohol at all. Cold-brew coffee and kombucha taps may be coming to companies such as Dunkin' and Starbucks. "I guess anywhere you see a line, we see an opportunity," he says.

At a similar company called Table Tap, business has shot up sixfold since 2016, according to founder Jeff Libby. He says he's installed self-serve taps not just at bars and restaurants, but co-working spaces and apartment lobbies in a bid to appeal to millennials.

But boomers have also been a surprisingly successful market, he says. "Senior living communities love self-serve beer," he says, laughing. "We put one in a senior living community and they are crushing it. They're having to cut people off!"

But doesn't cutting out servers, in the service industry, feel a little off? Libby concedes that many bartenders don't like self-serve beer. "I know that for a fact," he says.

But at Walters Sports Bar, I found a former bartender pouring himself a Death By Coconut, a porter from the specialty brewery Oskar Blues. "I have mixed feelings about it," says John Murphy, of the self-serve technology. "But I do love being able to just walk over and quench my thirst."

Grinning, he added: "And I'm always thirsty."

Ted Robbins edited this story for broadcast.