SEBASTOPOL, Calif. — California's big reds are coming on strong these days as winemakers pursue riper, fuller-flavored fruit.

A number of wines have been creeping past 14 percent alcohol and even into the 15- to 16-percent range, as opposed to the tamer 12- to 13-percent of years past. This is largely because vintners wait longer to pick their grapes. More mature fruit is thought to make tastier wine, but it also means sugar levels have a chance to rise, which comes with the side effect of pumping up the alcohol volume. Warmer harvests only increase the phenomenon.

Some are calling for a halt to the so-called "hot wines."

"I just hate high-alcohol wines," said Randy Dunn, founder of Dunn Vineyards, who fired off an open letter last year urging consumers to demand wines of 14 percent alcohol or less.

FANS AND OPPONENTS

Darrell Corti, president of Corti Brothers, a Sacramento wine and food market, is also in the less-is-more camp, announcing last year his store won't carry table wines over 14.5 percent alcohol.

Still, big reds, many of which are highly rated by critics, have their champions.

"They fill your mouth with flavor; you can chew on them. They linger on your palate when you're drinking them and that's what Napa is known for — its big, chewy cabs," said Doug White, director of operations for the Vintner's Collective, a Napa tasting room specializing in boutique wineries.

For those who don't like the big wines, some have an issue with the style of higher-alcohol vintages while others are wary of the punch they can pack.

One definition of the "right" alcohol level is if two people can finish a bottle and "wish there was a little bit more," said Dunn. "You don't do that with a 15.5 percent or 16 percent alcohol wine," he added. "You'd be lying on the floor."

It's not always easy to tell just how much alcohol is in a wine.

Wines containing 7 percent to 14 percent alcohol can be labeled just "table wine" or "light wine," as opposed to listing the alcohol content, under federal regulations. When a percentage is listed it can be off by up to 1.5 percent, a tolerance granted because one batch of wine may differ from another, said Art Resnick, spokesman for the Alcohol and Tobacco Tax and Trade Bureau in Washington, D.C.

Wines over 14 percent alcohol, which fall into a higher tax category, must list alcohol levels with a tolerance of plus or minus 1 percent.

The higher alcohol trend goes back about 10 years when growers started letting grapes stay on the vines longer to develop the full flavor of the fruit, said Kenneth Fugelsang, professor of enology and winemaster of the commercial winery run by California State University, Fresno.

California seems to have been a leader, although higher alcohol wines are also being made in other warm climates, such as Australia, he said.

WINE TECHNOLOGY

One way to have ripe fruit without high alcohol is to use various technologies to pull alcohol out of wine. But that's not something many winemakers want to talk about for fear of crushing the romantic vision of wine as an ancient art untainted by technology, said Clark Smith, co-owner and senior enologist of Vinovation, a company in the wine country town of Sebastopol that reduces alcohol levels through reverse osmosis.

The truth is that wine has already been affected by technology, from stainless steel tanks to sterile filtration, he said.

Unlike cooking, where chefs proudly show off new techniques, winemaking's become more secretive, said Smith. "It's a shame," he said, "because winemaking's just cooking."

Vinovation's process works by using filters that remove alcohol and water from wine. The two are separated by distilling and the water is then put back into the wine. To arrive at just how much alcohol should be taken out, Vinovation uses a method they call "sweet spotting," to find the point where the wine is at a lower level of alcohol but still tastes good.

Fugelsang, who uses Vinovation when his wine comes in with too much alcohol, sees the technology as "another tool in the winemaker's chest," but he understands why others are reluctant to open up about adjusting alcohol levels.

"I think a lot of it has to do with the fact that wineries don't want to be criticized by the wine press and others who harken back to wonderful wines they've had around the world that were just made with the hands of the winemaker and input from the grower," he said.

At Shafer Vineyards, a Napa Valley producer of highly rated reds, some coming in at 14.9 percent, winery president Doug Shafer won't use technology to reduce alcohol.

"We like our wines. We like the fruit. We like the richness," he said.

Shafer is aware of the debate over how much is too much, but says it's up to consumers to decide what style of wine they prefer. "I'm not forcing anyone to buy our wines — we're selling everything," he said.

Industry wide, "the quality of wines from around the world just keep getting better and better," Shafer said. "I think this is the golden age for the consumer."