How Does Wine Get Its Flavor?

Wine is the fermented juice of grapes. That statement does nothing to explain the complexities and subtleties of wine and its flavor. Wine gets its flavor from three different places: the grape itself, the climate where the grapes are grown and the winemaking process. If this were not true, it wouldn't matter if you were drinking a Beaujolais Nouveau, a Barolo from the Piedmonte or a California Cabernet: they would all taste the same. We know they don't, so there must be reasons why.

Each grape varietal is different. Some are sturdier while others are more delicate. Some will develop more sugar while growing than others. Just compare Cabernet Sauvignon to Pinot Noir. Wine drinkers know that a Cab is heartier than a Pinot. Growers know that Pinot is the hardest grape to grow, being very finicky about the soil and climate conditions in which it grows.

The climate in which a grape is grown has tremendous affect on the wine. A White Burgundy (which is a Chardonnay) has a different flavor than a California Chardonnay. This has somewhat to do with the amount of sunlight each vine gets, the length of the growing season, the mineral content of the soil and the temperature (or microclimate) of the region. The amount of sunlight and length of the growing seaon will determine the amount of sugar (and later alcohol) in a grape. French vintners in Burgundy will discuss how the soil on one side of a fence differs from the other side and how that results in differences in wines made from the two vineyards. and some people will argue that an Oregon Pinot Noir is better than one from California because "it's just too hot for the grape there."

The biggest contributor to flavor is yeast. It is the fermentation process that truly gives a wine its flavors. Let's take a quick look at what the yeast does. In order for a yeast to live it has to eat. and what it likes to eat most (like a lot of us) is sugar. In the process, the sugar is digested and ends up as two things—carbon dioxide and ethyl alcohol. Once all the sugar is gone, the yeast stop growing and eventually die. Sometimes, the yeast are killed by their own eating. What I mean is, the yeast produces so much alcohol that it can no longer stay alive in the vat, even if sugar is still present.

Wine vats
Wine-making vats

If that were the only thing going on inside a vat of wine, they would all taste the same. So let's get a little more complicated. Sometimes some oxygen is present in the vat, and the alcohol can be further converted into an acid (that's how vinegar is made). If conditions are right, the acid will not stay an acid but will combine with the alcohol or some other compound from the grape to form what is called by chemists an "ester." The important thing to remember is not how esters form but that they are the flavor compounds. When you say a white wine has a hint of apple or pear, or that a red wine has a berry-like character, it is because the esters in apples or pears or berries are present in the wine due to the extracurricular activities of the yeast. Speaking of extra activity, another good example can be seen in Chardonnays. If a Chard is "buttery," it is from the yeast working overtime and producing a compound called diacetyl—which also happens to give butter its flavor.

But, what about the alcohol? Ethanol, or ethyl alcohol—the byproduct of yeast fermentation—has no flavor of its own. By that I mean it does not trigger any receptors in the tongue or nose. It does have a effect, which results from the alcohol interacting with the cells in the mouth. If you are planning on using a wine in cooking, particularily if it will be reduced or simmered, the alcohol should have no effect on flavor.

And just what about these sulfites? A "sulfite" is a salt that is used by many winemakers to prevent oxidation of their wine. In other words, they add sulfite to prevent the wine from turning to vinegar before you get a chance to drink it (or they get a chance to sell it). All wines contain sulfites, whether they are added or not, because they are one of those extracurricular byproducts of yeast fermentation.

Cooking with Wine

Recipes for Cooking with Wine

Also see:

The Global Gourmet's Coq au Vermouth

About the author:

Joe LaVilla originally hails from Rochester, in Western New York State. While obtaining his Ph.D. in organic chemistry from the University of Rochester, he decided to pursue his culinary calling. A graduate of the Culinary Institute of America, Joe has worked in Manhattan, Washington, D.C. and at Spago in Las Vegas before settling in Phoenix.

For monthly "best" wine picks by a San Francisco tasting panel, don't miss Fred McMillin's On Wine.

This page originally published as part of the electronic Gourmet Guide between 1994 and 1998.