Techniques to make the most of a wine experience
Winemaking is an ancient endeavor that is part science, horticulture, precision and art. Making a good wine relies heavily on the skills of a winemaker, who must manage everything from the care of the grapes to the length of fermentation.
It may take the better part of a year just to produce the must — the fresh grape juice that marks the first step in wine production. From there it will take anywhere from 2 to 15 more years of aging to produce a fine wine.
There are many wine-producing regions in the world, from Europe (Greece, Italy, Spain, France, Germany), South America (Argentina, Chile), North America (Canada and the United States, particularly California, Oregon and Washington state) and New Zealand and Australia, each specializing in not only certain types of wine, but what types of grapes it can grow.
The success in growing wine grapes depends on four important traits: climate, temperature, soil and elevation. In fact, they’re so important the wine term terroir refers to how a region’s climate, soil and terrain affect a wine’s taste.
Climate and Temperature
In general, the warmer the climate (such as Greece, Italy, Spain), the more likely the region will produce red wines such as Cabernet Sauvignon or Zinfandel. This is because warmer climates allow grapes to fully ripen, which develops sweetness, fruit flavors, deep colors, and higher alcohol content.
Cooler climates (such as Germany and New Zealand), are more likely to produce white wines such as Riesling or Chardonnay, which are softer, crisper and lighter than most reds.
Macro- and microclimates within many wine regions, with variations on heat, rain wind and other weather patterns, allow them to grow both red and white varietals. France is known world-wide for both its reds, such as Burgundy and Beaujolais, and for whites such as Sauvignon Blanc, Chardonnay and Viognier.
Unlike other crops that rely on good soil, wine grapes do best when soil is low in nutrients. That’s because vines spend more energy on basic survival and produce fewer grape clusters—and fewer grape clusters mean juicier, sweeter grapes. As a result, vineyards with sandy soil produce lighter wines, while vineyards with clay soil produce bolder ones.
Elevation also plays a role in how grapes grow. Vines at higher elevation typically get cooler nighttime temperatures and longer growing seasons, resulting in grapes with a higher acidity. Vines on hills and mountains tend to get more direct sunshine, leader to deeper colors and stronger tannins.
From Vine to Bottle
In the Napa Valley, the production of the must typically begins in January and February with winter pruning of dormant vines. Vineyard workers prune and train the vines to grow in specific directions to make the most of new grape growth.
Soon, the vines produce the first leaves of spring and then develop clusters of tiny flowers that grow into grapes. Workers take care to ensure that frost and wind don’t damage the flowers or young grapes, using heaters or large fans to circulate and warm the air around the vines.
In the spring, the vines grow rapidly, and workers turn their attention to thinning shoots and removing certain leaves. This helps ensure fruit uniformity and makes the most of exposure to sunlight and air. Midway through the growing season, the vines are thinned so that the they produce a lower quantity but higher quality crop. In other words, the crop is deliberately limited so that its yield produces bigger and better grapes.
By midsummer, the grapes finally begin to show their final color. This pigment development is called verasion, and may last for months.
Vineyard workers begin to harvest the grapes in the fall. The exact timing of picking the fruit is made by the winemaker, who determines whether the grapes have the necessary balance between sweetness and acidity. Harvesting can be done by hand or by machine, and is often done at night so that the grapes remain cool. Once they’re at the winery, the grapes are sorted sorted to remove under- or overripe fruit.
Pressing and Crushing
After the grapes are sorted, they’re crushed with a mechanical press into must (the mixture of grape juice, skins and seeds). Winemakers will quickly remove the solids for a white wine; for red wines, the skins remain in the must so that the wine develops with additional color and tannins for flavor. Reds are pressed before fermentation, and are only fully crushed after fermentation is complete.
After the grapes are pressed, they’re fermented. Fermentation occurs naturally with the presence of yeasts in the air, but winemakers usually add a cultured yeast to ensure the wine develops correctly. Fermentation occurs until all of the sugars present in the must are converted to alcohol. This can take anywhere from 10 days to month, and results in a dry wine.
After fermentation, the solids, yeast and tannins are removed, having only liquid. The wine is then transferred, or “racked,” into oak barrels or stainless steel vats for aging.
Bottling and Aging
Depending on the type of wine, the aging may take several months to several years for the wine to reach its maturity. For reds, the winemaker may bottle the wine and store it for an additional 18-24 months of aging.
Aging in Oak Barrels
Once the grapes are harvested, they must be aged to allow fermentation into wine. Most vineyards choose to age grapes in oak barrels, a tradition that goes back to a time when there was no other practical way to store or transport wine. As it happens, the oak imparts a flavor to wine which it has become a key characteristic.
Within the oak are vanillin compounds which, yes, taste like vanilla. Other flavor notes can be present in the wood, such as fruit, dill, cloves, smoke or spices. As the wine sits in the barrel over time, the flavors leave the barrel and imbue the wine. The intensity of the flavors depends on the type of oak, where it was grown, and how old the barrel is.
The barrels also promote two other changes to the wine: they allow in a small amount of oxygen, which results in a smoother taste; and they allow fermentation to take place, making the wine taste creamier. Typically, French or European oak is more dense and allows in less oxygen, making it more suitable for lighter or white wines. American oak is preferred for more robust wines like Cabernet or Petite Syrah.