Mysterious underground lairs are perhaps best known for housing bats and crime-fighting operations, but for wine enthusiasts, they offer more than a literal and figurative cool factor. Subterranean storage is far superior to climate-controlled warehouses and specialty refrigerators for caching bottles from harvest to consumption. In other words, although candlelit caves may seem designed for atmospheric drink-ups or dinner parties (not to mention superhero hideaways), they serve a serious purpose. Best of all, with modern technology, it is increasingly possible for mere mortals to create them.
Why Caves Work
First of all, caves are dark. Light poisoning doesn’t get nearly as much attention as heat damage when it comes to wine, but sunlight and even bright light bulbs can deteriorate wine through glass bottles. (This is why high-end wines and those destined for aging generally come in very dark green or black glass.) Bottles stored underground are not exposed to the sun directly or through windowpanes.
Caves also trap humidity, which slows wine evaporation. That means fewer hours spent topping up barrels, and more wine produced every year — anywhere from three to four gallons more per barrel. That may not sound like much, but multiplied across 100 or 500 barrels, that’s an immense amount of wine and even more money.
Similarly, humidity keeps corks from drying out in finished wines, allowing them to age deliciously instead of becoming oxidized and vinegary.
Most importantly, subterranean temperatures are far more stable than those above ground. Away from the sun and insulated by layers of earth, underground storage temperatures usually vary by just one or two degrees, whereas surface levels undergo 50-degree swings. These fluctuations cook wine that is aging or fermenting like a stove, turning it from fruity juice to sour, brown swill in just a few days — or hours.
That natural insulation is a huge financial plus for wineries with caves. Built-in temperature stability means thousands of dollars saved on annual heating and cooling costs, which make up a large part of any winery’s expense report.
Lower energy requirements also make caves an eco-friendly triple threat: They’re gorgeous, practical, and sustainable.
How to Build a Cave
Anyone with a basement already has the makings of a perfectly functional wine cave. But for winemakers who didn’t inherit an ancient family cellar, or whose facilities tragically lack a basement, technological advances make it increasingly possible to build a modern cave.
As with harvesting wine, building a cave gets easier or harder depending on soil. In California, where volcanic soil is common, road construction machines are often used to drill into the earth. Builders drill the design of the cave into the ground like a stencil, and then go deeper.
In areas like the Northeast, it’s easier to use a simple dig-and-fill method, akin to pouring a foundation for a house. It’s then covered with earth before the inside is finished.
In soils laden with heavy boulders, science comes to the rescue. A small hole drilled into the boulder is filled with a chemical solution that dries and expands, fracturing the rock into movable pieces. And when all else fails, there’s always dynamite for blasting into stubborn ground or hillsides.
Once hollowed, sprayable concrete is used to waterproof and stabilize, after which the simple structure is ready for use.
New-build wine caves are an investment, but one that many wineries, collectors and enthusiasts are increasingly opting to make. When wired with electricity, running water and drainage capacity, building costs can accumulate; however, long-term savings on energy and acreage cannot be beat.
Whether you’re a budding vintner analyzing profit and loss statements, or a homeowner wondering what to do with that unfinished basement, think wine cave. Batman would approve.