(FORTUNE Small Business) – Jeff smith was between jobs a few years back and pitched in to help his father, Joe, move to a new house in Beverly Hills. Joe--a former chairman of Warner Bros. Records, Capitol EMI Records, and Elektra Records--is known mainly for two accomplishments: signing the Grateful Dead and collecting 5,000 bottles of fine wine. After the move, Jeff Smith, 43, who shares his dad's love of wine, organized the wine cellar; a family friend saw the results and asked Smith to do the same for him. "He paid me $500, and that's when the light bulb went on," says Smith. "Here's a guy who owned just 300 bottles, yet didn't know how to manage it. When you have thousands of bottles, you really lose track of what you have."

So began Carte du Vin, Smith's foray into the cool, dark depths of fermented clutter. A year ago he turned the spare bedroom of his Hollywood Hills house into an office and invested $3,000 in a laptop, BlackBerry, and portable printer; $3,000 in a website; and $2,700 in customized software. That program categorizes wine by variety (chablis, zinfandel), vintage, critics' ratings, peak drinking date, and price.

Smith charges $2 to $2.50 a bottle to inventory and organize a cellar any way a client wants: say, by wine type and region, with the oldest vintages on top. He delivers the resulting cellar inventory on a spreadsheet, in a leather-bound list, and on a password-protected website. Many clients hire him for monthly cellar maintenance, at $100 an hour. He grossed $150,000 last year.

Two part-time employees help Smith open crates and shelve bottles, and another part-timer handles the wine research. (His database contains information on some 10,000 wines.) The work can be dusty and cold--the typical cellar temperature is 55 degrees--but Smith doesn't mind. "This is a little like looking at someone's baseball card collection. Every once in a while you come across the Babe Ruth card," he says. "One of my clients has about $1.5 million worth of wine. My first time working there, each case I opened was more fabulous than the next. I was like, 'Oh, my God, a 1947 Cheval Blanc!' "Then there was the time he discovered a phony wall in a cellar. Behind it were "tons of guns and all this ammo. It was wine and weapons. I just worked quickly," he says.

All of Carte du Vin's clients--about 60--are referrals. Smith's approach to marketing is spare: an elegant brochure and socializing. "I do a lot of entertaining, I go to wine tastings, I pour wine for my clients," he says.

Sometimes he stays for dinner. Last summer, after spending two days organizing a 2,000-bottle wine closet in the Long Island home of Lonny Schwartz, a CEO, Smith wound up a dinner guest. "I said to Jeff, 'You choose the wine,' and he did," says Schwartz. "Believe me, it was great."