July 12 (Bloomberg) -- The other night I dumped a $75 Sonoma merlot down the drain. Why? The wine had a hot aftertaste that reminded me of the flamethrower finish of bad grappa. OK, maybe I shouldn't have been surprised. The fine print on the label said it contained a whopping 15 percent alcohol.

Over the past decades, alcohol levels in wine have been racheting up ominously. In the Napa Valley, the average climbed to 14.8 percent in 2001 from 12.5 percent in 1971. Even some once-delicate Oregon pinots are hitting 14 percent to 15 percent and taste more like syrah.

Welcome to the age of overpowering wines.

Call my vino dumping a personal rebellion against the latest wine-fashion craze, but don't mistake me for some neo- prohibitionist member of the anti-pleasure police. Alcohol is an essential component of wine, contributing body and texture. What I object to is that too much of a good thing is changing the taste of contemporary wine.

High-alcohol wines have a sweet, rich, thick character, but many also taste heavy, smell of prunes and raisins, and lack both subtlety and the savory freshness that makes the beverage great with food. And guess what? Few age well, either.

The discussion heated up recently when much-respected retailer Darrell Corti of Corti Brothers in Sacramento, California, decided that his store would no longer carry wines with alcohol above 14.5 percent.

`Take a Stand'

``We were tasting eight zinfandels, whose alcohol levels ranged from 14.6 to 15.6 to 17 percent,'' he said in a phone interview. ``They didn't taste good. Sometimes you have to take a stand.''

Wine lovers immediately weighed in on the blogosphere, some calling his action senseless censorship, grandstanding, even a police-state mentality. Corti reports that customer e-mail responses are mostly supportive. ``They're tired of table wines that taste like port,'' he said.

Earlier this year, Sue Daniels, wine technologist in the U.K. retailer Marks & Spencer's food division, told Decanter magazine that the chain planned to seek out wines closer to 12 percent than 14 percent.

There's no consensus on a single cause for rising alcohol levels, so don't automatically blame global warming. One culprit is the practice of letting grapes hang on the vine longer to get riper and riper. The more sugar in the grapes when they're harvested, the more alcohol in the wine after fermentation.

First Impressions

The practice is driven by the fashionable trend toward more concentrated, bolder-flavored wines that sacrifice balance for the all-important first impression. But recognizing that it doesn't matter how breathtaking the first glass is if consumers don't want to finish the bottle, some winemakers are looking for ways to get the flavor they want without the turbocharged alcohol levels.

The solution for many is to call lab wizard Clark Smith.

So when Smith, a winemaker and founder of consulting firm Vinovation in Sebastopol, California, invited me to experiment with finding the ideal level of alcohol in a particular wine, I was eager to try.

In the early 1990s, Smith developed a way to remove alcohol from wine with a process called reverse osmosis. Smith says he works with about 1,200 wineries worldwide and estimates that about 45 percent of all California premium wines are alcohol- adjusted. Few will admit using his services; one who does is winemaker Randy Dunn, noted for his collectible Dunn Vineyards cabernets.

With his patented technique, Smith can reduce a wine's alcohol to any percentage a winery chooses. But he claims each wine has a couple of alcohol ``sweet spots'' where the wine tastes best.

``It's all about harmony,'' he said. ``The musical paradigm is the paradigm of how wine works.''

Changing Taste

He poured me glasses of 2005 Amador County syrah from four test bottles. All contained the same wine, but each had a different alcoholic strength. I was amazed that adjusting the alcohol could change the wine's taste so much.

The first, at 15.4 percent alcohol, seemed hot and super- rich. The 14.2 percent wine was jammy, with a fresher nose and brighter flavors, though my favorite was the 13.75 percent bottling, which seemed spicier, with fruit and leather notes, more Rhone in style. Smith says a table wine's sweet spot is rarely more than 14.5 percent.

I'm dubious of most high-tech fiddling in the wine cellar, but if reverse osmosis is what it takes to turn a brutish wine into a balanced one, maybe it's not so bad. (Smith offers a four-bottle sampler of alcohol-adjusted wines under his WineSmith label for $59.)

On the other hand, wouldn't it be simpler for wineries just to change what they do in the vineyard and pick earlier?

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

To contact the reporter on this story: Elin McCoy at emcwine@aol.com.

Last Updated: July 12, 2007 00:10 EDT