This high-tech, Bavarian bunker is secretly storing the world’s finest wines

Cases of rare vintages line the shelves of the Unger Weine bunker, all in a controlled environment supervised by computers
Sam Chick

When the Unger Weine storage cellar was being built in Frasdorf, a tiny village in the foothills of the Bavarian Alps, a local approached Michael Unger, the company’s co-founder, and gazed at the vast hole being hewn out of the limestone and marble rock. This, he determined, must be something for the military: no one would spend eight months digging a hole like this just for wine.
Nowadays the comments are rather different. Above ground stands an elegant, traditional Bavarian house, with sloping roofs, timber walls and latticed balconies looking out over the meadows. As well as the offices of a wine-trading business recognised as one of Europe’s finest, it serves as a picturesque venue for tasting events and hospitality. “We get complimented on how well we’ve restored this old farmhouse,” Unger says. “People don’t realise that we built it from scratch.”


People are also unaware that lying beneath, accessed by a single stairway, is a dark, silent stronghold for a multitude of the rarest and most sought-after vintages on Earth – the kinds that justify security measures worthy of a bank vault, and a computer-controlled climate ensuring temperature, humidity and even vibrations (or a lack of) are managed to the finest degree.
It is not, Unger explains, the kind of facility where owners might expect to drop in to pick up a few bottles for a dinner party. “We store everything by the case, we deliver by the case and we even do the logistics underground to ensure as little disturbance as possible,” he says. “If someone goes into the cellar, it changes the humidity, light and temperature too much.”

Michael and Wulf Unger in the delivery receiving area
Sam Chick

In fact, a chip-coded key access system records every door opening and closing, who used it and how long they spent inside. That’s crucial for minimising disruption to the wine, but also to the security of a bunker whose contents are searingly valuable.


From walls of cases of hard-to-get Premier Cru blockbusters to cult spectaculars like California’s Screaming Eagle (upwards of $3,000 a bottle if you can ever track one down), Unger Weine’s in-house portfolio is like a who’s who of the desirable, the unobtainable and the untouchable. And it shares the cellar’s 5,000 square metres with privately owned collections from clients across Europe and, increasingly, from around the world. Some have as many as 500 cases stored, which may end up here for decades, if not generations.
“Most people call their cellars ‘cellars’, but they’re not a cellar,” says Unger, a former engineer in the luxury car industry, who founded the wine-importation business with his brother Wulf, an economics PHD, 30 years ago. In 2007, they opened a storage facility for their stock, but the subsequent boom in investment buying, and ensuing demands from private customers for extra storage space, convinced the brothers to go a stage further.
“We said: let’s build something, but if we do, it has to be a benchmark,” Unger says. Construction took four years, with “Der Keller” opening in 2015. “For me as an engineer, technology was key to creating something that is unique in the wine industry.”

Michael Unger authenticates a bottle of Château Lafite Rothschild
Sam Chick


Unger points out that many of Europe’s old chateaus and mansions have cellars packed with wine, but without temperature and humidity controls. “And of course, temperature has changed compared to 50 years ago. Room temperature for wine is different now.”
For wine storage, climate is everything: if humidity is too low, or the temperature too high, evaporation through the cork or oxidation from air seepage can cause the ruination of a fine vintage. “The delta between inside and outside the bottle should be as small as possible,” says Unger, who aims to maintain humidity at 70 per cent and the air temperature at 10-15 degrees Celsius – “running as close as possible to the point where the air is saturated, without going over it.”
To do that in his Bavarian bunker, a complex suite of heating, cooling and air-filtration systems was designed, and is managed via bespoke computer software. At its heart, a combination of geothermal heat exchange from the groundwater, topped up with heating from locally sourced wood pellets, runs through a radiation-based system embedded in the floors and ceilings that can be precisely managed up and down, while an air-cooling system designed for hospital isolation wards is used to constantly filter the airflow.

Michael Unger ascends the main cellar staircase. Designed by architect Peter Höflinger, it’s 12 metres deep
Sam Chick

“We use the aircon as a backup system,” says Unger. “We try to use the [geothermal] system more, but that’s a very complex mix for any engineer to deal with. My technical background helped a lot.”
In August, torrential summer storms resulted in power lines to Frasdorf, which lies an hour outside Munich, being cut – a potentially devastating situation for such a finely tuned technical operation. It turned out to be the ideal stress test for Unger Weine’s back-up generator. “When the electricity goes off, it goes on a battery system to give the generator 20 seconds to power up. We only knew there had been an outage because the phone lines went.”
As much as a particularly obsessive curator of wines, Unger is an asset manager with millions under management, in a sector that is maturing nicely as other areas of the market look decidedly corked. “Interest rates have stayed so low, and investments are getting more and more risky and unprofitable. We’ve seen even more demand since the pandemic began,” he says. “You have to pay to keep your cash, and people don’t trust it. So why shouldn’t you pay to keep an investment that you can sometimes consume and enjoy?”
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