Dec. 14 (Bloomberg) -- What the espresso machine was to the 1990s, the home wine cellar is to the 21st century.

At my local Home Depot earlier this month I spotted shoppers snapping up 16- to 50-bottle mini-cellars that sit on or under the kitchen counter. With prices ranging from $90 to $1,500, sales are booming at chains like Target, Best Buy, Lowe's and Costco. A couple of years ago, home cellars were specialty items only for wine geeks or rich collectors.

A 2005 Association of Home Appliance Manufacturers study found that 4.3 million households in America now have wine cellars, with more than 3 million purchased since 2003. The most popular are small models typically made in China, reports Barbara Insel, managing director of Napa Valley's MKF Research, which has followed the trend. Bestselling inexpensive brands such as Haier and Danby have now been joined by prestige names like Sub-Zero.

Many wine lovers are quick to trade up to bigger free- standing units that offer more options.

Newbie wine collector Kim Caldwell started out a year ago with a 57-bottle GE Monogram ($1,000) in her kitchen. But the 43-year-old Long Island certified financial planner kept acquiring pricey bottles of Barolo and Bordeaux. Last spring she graduated to a black, 158-bottle EuroCave cabinet ($3,500) with an elaborate cooling and humidity control system and a glass door to show off the contents. She calls her kitchen unit a cellar ``for near-term drinkers.''

Sales Up 30 Percent

``Protecting your investment and being able to enjoy wine at its best are the main benefits,'' says Adam Strum, chairman of Wine Enthusiast Cos., whose main business is wine storage units, including the EuroCave. The company has sold half a dozen lines through its catalog since 1983 and wholesales to chains. Strum says cellar sales are up 30 percent this year, with the EuroCave line pulling in $30 million.

There's a reason for this growth: Unless wine is kept in a dark, vibration-free environment at a constant temperature of about 55 degrees, with 60 percent to 70 percent humidity, it ages prematurely and eventually turns lifeless and flat.

Research commissioned this year by Scotland's Standard Life Bank found that Brits end up pouring the equivalent of 87 million bottles of wine down the drain each year because it wasn't stored correctly, according to Ashley Ramsay, the bank's marketing manager.

Most low-cost units maintain the optimum temperature but lack humidity control, so they're best for short-term storage. On the other hand, they're vastly superior to stashing wines in a hot kitchen cupboard. That's vinocide.

After the $10,000 Stove

There's also a big ego factor in owning a wine cellar.

``After the gourmet kitchen with the $10,000 stove, a wine cellar is next. It signals you're sophisticated,'' says Elliott Mackey, owner of California's Wine Appreciation Guild, which has sold wine storage units since 1973. He estimates the home cellar market in America is now a $1 billion-plus retail business.

Eventually, serious collectors like 34-year-old Tim Rankin, managing director of investment firm Blue Harbour Group in Greenwich, Connecticut, dream of a custom walk-in cellar.

Rankin had spread his 2,500-bottle collection of Barolos, Bordeaux and Rhones among freestanding units and off-site storage, but he yearned to consolidate. This month he's having a cellar constructed in an old garage bay of his new home. ``It will hold 4,500 bottles, so there's room to grow,'' he says.

Design firms specializing in building high-end custom cellars report that business is up significantly even with price tags of $10,000 to $500,000 or more. That doesn't include wine, of course.

For the past year, Wine Enthusiast has been sending master craftsman John Seitz across the country in an RV to consult with customers and then build their cellars. He's completed eight in the past two months.

Elaborate Cellars

Architect Evan Goldenberg, owner of Connecticut-based Design Build Consultants, who's been in the business for 13 years, now grosses $5 million a year.

``Cellars have gone from no-frills to very elaborate,'' he says. He recently finished a 40-foot-square, 18,000-bottle cellar with Honduran mahogany wine racks, French limestone floors and a ``smart controller'' that will notify the owner on his BlackBerry if the temperature and humidity controls fail.

Hey, who wants to end up pouring 18,000 bottles of wine down the drain?

For more information about wine storage units, see http://www.wineenthusiast.com, http://www.wineappreciation.com and http://www.customwinecellars.com.

(Elin McCoy writes on wine and spirits for Bloomberg News. The opinions expressed are her own.)

To contact the writer of this story: Elin McCoy at emcwine@aol.com.

Last Updated: December 14, 2006 00:02 EST