If you tour a winery during harvest, you might be surprised to see stacks of industrial-sized bags of sugar. No one's making grape jelly or getting a jump on holiday baking. The sugar goes into the vats before or during fermentation in order to raise the alcohol level of the finished wine.
This age-old winemaking practice is called chaptalization, after Napoleon's minister of agriculture, Jean-Antoine Chaptal, who helped popularize the practice. The technique long predates the 19th century, however; it can be traced back at least to Roman times, when vintners already recognized the virtues of adding honey to their must. The Romans didn't understand the mechanics of fermentation--during which yeast metabolizes sugar to form ethyl alcohol (ethanol) and carbon dioxide--but they knew a good thing when they tasted it.
Alcohol accounts for much of a wine's body: the sense of weight and depth in the mouth. It also helps volatilize the fruit character to convey more richness and an impression of sweetness. The natural level of alcohol depends on the amount of sugar in the grapes, which, in turn, depends on how ripe they are at harvest.
The level of alcohol at which a wine is considered balanced has varied over time. In 19th century Bordeaux, many red wines had 10 degrees potential alcohol (after bottling, degrees of alcohol is alcohol by volume before chaptalization and fermented to total dryness) or less. Modern production techniques generally aim for richness and power; this requires harvesting riper grapes, which in turn yield more-alcoholic wines. But nature doesn't always cooperate with winemakers who are seeking 13 to 14 degrees of alcohol. In difficult vintages, growers can struggle to achieve the desired sugar levels in their grapes.
The 1997 Oregon Pinot Noir harvest is a case in point. When storms started on Sept. 30 and didn't stop, Doug Tunnell, owner and winemaker of Brick House in the Willamette Valley, knew that delaying harvest would only result in diluted grapes. "If I let the fruit hang, I would have had Pinot Noir rosé," he says.
So he picked grapes from one of his blocks with about 12 degrees potential alcohol--1 degree less than he wanted--and chaptalized enough to make up the difference.
Laws regulating winemaking practices (generally) respond to the realities of viticulture within a region. So in cooler areas, such as Oregon, Bordeaux, Burgundy and Long Island, N.Y., chaptalization is perfectly legal, though there are restrictions on the quantity of sugar that may be added. In the Champagne region of northeastern France, chaptalization is essential; in order to make suitable base wines, winemakers need to harvest grapes with such pronounced acidity that the sugar might provide no more than 8.5 degrees of alcohol. (This chaptalization is distinct from dosage, the addition of a sugar-wine solution that occurs just prior to corking.)
Adding sugar is illegal in many warmer regions, such as California and Italy. (Though, curiously enough, winemakers in these regions can add syrupy grape concentrate.) But sometimes, California vintners want to chaptalize--and some do, regardless of the rules. In 1989, for example, the combination of large, slow-ripening crops, cool weather and harvest rains made for very low sugar in many grapes. Chaptalization was one solution. "Some of us indulged in the practice to make something decent from a rough vintage," acknowledges a prominent Napa winemaker.
For years, sugar additions were practically universal in Bordeaux. A California winemaker who spent a year in the early '80s at a Bordeaux first-growth recollects that the chteau enologist decided before harvest to make a wine with 12 degrees alcohol--so every vat of grapes received precisely enough sugar to attain that target.
But most enlightened vintners are now less rigid about alcohol. "There is no ideal level," says influential consultant Michel Rolland, who works with wineries in 12 countries. "With good wines, I don't care about the alcohol level. Even if it's a question of 15 degrees, it doesn't matter. Good wine has balance, which means everything is integrated."
Savvy vintners consider a variety of factors at harvesttime. As grapes ripen, sugar (the potential alcohol) increases, acidity decreases, tannins become rounder and flavors become progressively less vegetal and more fruity. More often than not, however, these components don't develop in perfectly choreographed lockstep.
Pierre Lurton, winemaker and managing director of Château Cheval-Blanc in Bordeaux, harvests his vineyards early enough to preserve lively acidity in the Merlot. "I like to pick the Merlot early to preserve freshness," he says.
To preserve that freshness, Lurton sometimes picks before he has ideal sugar. In the superb 1998 Cheval-Blanc, he added enough sugar to increase alcohol 1 degree in about 8 percent of the crop. In more challenging years, such as 1997 and 1992, he chaptalized a bigger portion of the harvest.
Lurton and Rolland agree that chaptalization is not as prevalent in Bordeaux today as it was 10 or 15 years ago. Quality winemakers now seek riper, richer flavors and so wait longer to harvest. Producers also reduce crops, which means that the grapes ripen faster.
High technology also has supplanted chaptalization at many wineries. Rather than raising alcohol with sugar additions, producers achieve similar ends by removing water from either the unfermented juice or the wine by means of reverse osmosis or other evaporative techniques. However, these modern techniques amplify both the good and the bad, so producers who apply them to must or wine made from unripe or damaged grapes will also intensify unpleasant flavors.
In Burgundy, with its cool northerly climate, chaptalization is commonplace. "Everyone does it sometime. All the winemakers add sugar," says Michel Niellon, owner and winemaker of Domaine Niellon, a top producer in Chassagne-Montrachet.
There is a variety of ways to chaptalize: The choice depends on the type of wine and the winemaker's goals. Gevrey-Chambertin winemaker Claude Dugat adds sugar to his Pinot Noir toward the end of fermentation. Untended Pinot Noir ferments very quickly, usually taking no more than six or 10 days. Incremental sugar additions extend the process, allowing Dugat to get more tannin extraction, an important benefit in a grape that often lacks structure.
The timing is important. "If one adds [sugar] at the beginning, the fermentation gets too hot [which can damage the yeast]. So I wait until the temperature goes down a bit," Dugat says. In contrast, Niellon, who makes predominantly white wines, ferments in barrels (rather than in large vats), so fermentation temperatures stay fairly low. He adds sugar right after the grapes are pressed, usually enough to bring the wines to 13.5 degrees of alcohol.
Most winemakers use cane sugar, though beet sugar and corn syrup are also options (brown sugar, though illegal, has its fans because of the molasses and caramel flavors it contributes). Typically, the sugar is liquefied with juice from the must, then pumped into the vat. Slightly different quantities of sugar are needed, depending on the type of wine and the production techniques. With reds, 116 pounds of sugar added to a 700-gallon vat will raise alcohol about 1 degree.
Wines fermented in open vats (such as many Pinot Noirs) lose about 1 degree of alcohol due to evaporation, so producers might need to offset that loss with sugar.
Like all winemaking and viticultural practices, chaptalization demands restraint. The alcohol fermented from added cane sugar tastes the same as alcohol from grape sugar (ethanol is ethanol), but over-chaptalized wines are unbalanced and boozy. If they don't have sufficient fruit concentration, the alcohol seems excessive.
Perhaps the greatest potential drawback to chaptalization is that it gives vintners a crutch. They know they can add sugar, so there's temptation to grow large crops that ripen slowly and have less concentration. And given access to "sunshine in a sack," why accept the risks inherent in delaying harvest waiting for that added measure of ripeness?
But quality winemakers recognize that chaptalization will never transform poor grapes into good wine. Used judiciously, it's a tool that allows vintners to achieve the style and balance they desire. "Sugar is one thing and maturity is another," says Niellon. "Sugar doesn't replace maturity, it doesn't give perfume or ripe fruit."