Wine caves: Just how much do these things cost?

Thursday night’s Democratic presidential debate rocketed the existence of wine caves — not mere wine cellars, but subterranean caves bored into rock for the aging and consumption of wine — into America’s consciousness.

Sen. Elizabeth Warren  (D-Mass) criticized Pete Buttigieg for attending a fundraiser inside a Napa Valley winery’s crystal chandelier-lit cave. “Billionaires in wine caves should not pick the next president of the United States”  back and forth over wine caves set social media ablaze -- surprising those in the wine cave industry.

“I do find it very entertaining that a wine cave is a topic of a Democratic presidential candidate debate,” Rick Shone, president of winery contracting firm Nordby Wine Caves told FOX Business.

And on Friday the politicos continued to mine the wine cave. Sen. Bernie Sanders (I-Vt) dinged Buttigieg said, “Unlike some of my opponents who have super PACs, my other opponents who are going to wealthy peoples’ homes and wine cellars, this campaign is funded by the working class of this country,” Sanders said during a campaign event.

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Wine caves aren’t actually anything new. Vacationers in Europe can still visit ancient Roman wine caves. But they’ve become a hip attraction for wineries over the past two or three decades, according to Shone.

Traditionally the caves have been built for barrel storage, since the caves naturally have steady temperatures and humidity levels that are good for wine production.

“But then people discovered their clients and wine club members liked to go inside,” added Shone, “There’s this cool factor, this mysterious quality to them and they starting opening tasting rooms and event centers inside.”

That led to more and more wineries using wine caves for entertaining visitors. Caves are also becoming more popular with private owners, according to Shone. He said Nordby recently worked on an 800-square-foot cave for a California homeowner. And some owners are turning to manmade caves for other purposes, such as storage of valuables like cars or art and protection from California’s wildfires.

“It’s a practical application for some people,” Shone said.

PETE BUTTIGIEG’S WINE CAVE EXPERIENCE NOT JUST FOR BILLIONAIRES

The caves also come with “overwhelming energy efficiency benefits,” according to Mark Anderson, president of CC Wine Caves. He said aging wine in a cave can reduce the amount of energy consumed from farm to table by 50-60 percent and other types of agriculture could also benefit from cave storage.

“It’s not just about wine … everything from farm to table is refrigerated,” he said. “Wine is just the only industry, in my experience, from agriculture that has the point spread from profits to earnings to actually do a capital investment of that nature”

So how much does all this cost? Various wine cave contractors who spoke to FOX Business quoted typical prices ranging from $200 to $400 per square foot. But many factors can affect the price, including local geology, tunnel size and the desired finishes, according to David Provost of Bacchus Caves.

“We’ve had owners who want very utilitarian finishes,” he said. “Other owners want the Venetian plaster or very fancy stonework or tile inside.”

Provost said he’s built caves ranging from literal bat caves — for an owner who wanted more bats on his property — to a subterranean spa with an underground waterfall.

“It’s really an incredible structure,” he said of the spa.

In the case of Buttigieg’s fundraiser, the event was held in the cave at the Hall Rutherford winery, The Associated Press reported. The 14,000-square-foot cave is built from Austrian bricks according to the winery’s website and features a chandelier with 1,500 Swarovski crystals and an onyx banquet table, according to the report.

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