Grape Growing: The Basics Overview

Most kinds of wine grapes are touchy. If the weather is too hot, they can produce too much sugar and not enough acid, resulting in overly alcoholic wines. Too cool and they won't ripen properly, and some will develop an unpleasant vegetal taste. And rain at the wrong time of year can wreak havoc on vineyards, causing grapes to rot on the vine. What's more, the wrong type of soil can leave vines with "wet feet," which can seriously hamper their growth. These and many other conditions must be just right to coax the best out of persnickety wine grapes, and Napa and Sonoma have that magical combination of sun, rain, fog, slope, and soil that allows many varieties of wine grape to thrive.

Appellations: Location, Location, Location

California growers and winemakers generally agree that no matter what high-tech wine-making techniques might be used after the grapes are picked, in fact the wine is really made in the vineyard. This emphasis on terroir (a French term that encompasses a region's soil, microclimate, and overall growing conditions) reflects a belief that the quality of a wine is determined by what happens before the grapes are crushed. Even a small winery can produce spectacular wines if it has the right location and grows the grapes best suited to its soil and microclimate.

In the United States, the Alcohol and Tobacco Tax and Trade Bureau (TTB) designates appellations of origin based on political boundaries or unique soil, climate, or other characteristics. California, for instance, is an appellation, as are Napa and Sonoma counties. More significantly to wine lovers, the TTB can designate a unique grape-growing region as an American Viticultural Area (AVA), more commonly called an appellation. Whether the appellation of origin is based on politics or terroir, it refers to the source of a wine's grapes, not to where it was made.

Different appellations—there are more than 100 AVAs in California, with 16 in the county of Napa alone—are renowned for different wines. The Napa Valley is known for Cabernet Sauvignon, for example, the Russian River Valley for Chardonnay and Pinot Noir, and the Dry Creek Valley for Zinfandel. Wineries can indicate the appellation on a bottle's label only if 85% of the grapes were grown in that appellation. Many wineries buy grapes from outside their AVA, so they might label different wines with the names of different regions.

What makes things a little confusing is that appellations often overlap, allowing for increased levels of specificity. The Napa Valley AVA is, of course, part of the California appellation, but the Napa Valley AVA is itself divided into even smaller subappellations, the Oakville and Rutherford AVAs being among the most famous of these. There are even subappellations within subappellations. Over in Sonoma County, the Russian River Valley AVA contains the smaller Green Valley of the Russian River Valley AVA, which earned status as a separate viticultural area by virtue of its soils and a climate cooler and foggier than much of the rest of the Russian River Valley.

When it is to their advantage, winemakers make sure to mention prestigious appellations, and even specific vineyards, on their labels. If the grapes have come from multiple AVAs within a given region—say, the North Coast—the wine can be labeled with the name of the whole region. Wines simply labeled "California" are usually made of grapes from more than one region.

Geology 101

Wherever grapes are grown, geology matters. Grapevines are among the few plants that give their best fruit when grown in poor, rocky soil. On the other hand, grapes just don't like wet feet: the ideal vineyard soil is easily permeable by water for good drainage. Until the 1990s, California growers were more interested in climate than geology when deciding where to plant vineyards and how to manage them. As demand for premium wine exploded, though, winemakers began paying much more attention to the soil part of the terroir equation. Geologists now do a brisk business advising growers.

Different grape varieties thrive in different types of soil. For instance, Cabernet Sauvignon does best in well-drained, gravelly soil. If it's too wet or contains too much heavy clay or organic matter, the soil will give the wine an obnoxious vegetative quality that even the best wine-making techniques cannot remove. Merlot, however, can grow in soil with more clay and still be made into a delicious, rich wine. Sauvignon Blanc does quite well in heavy clay soils, but the winegrower has to limit irrigation and use some viticultural muscle to keep the grapes from developing unacceptable flavors. Chardonnay likes well-drained vineyards but will also take heavy soil.

The soils below Napa Valley's crags and in the valleys of Sonoma County are dizzyingly diverse, which helps account for the unusually wide variety of grapes grown in such a small area. Some of the soils are composed of dense, heavy, sedimentary clays washed from the mountains; others are very rocky clays, loams, or silts of alluvial fans. These fertile, well-drained soils cover much of the valleys' floors. Other areas have soil based on serpentine, a rock that rarely appears aboveground. In all, there are about 60 soil types in the Napa and Sonoma valleys.

In Wine Country you'll hear a lot about limestone, a nutrient-rich rock in which grapevines thrive. Some California winemakers claim to be growing in limestone when in fact they are not. In fact, only small patches of California's Wine Country have significant amounts of limestone. The term is often used to describe the streak of light-color, almost white soil that runs across the Napa Valley from the Palisades to St. Helena and through Sonoma County from the western flanks of the Mayacamas Mountains to Windsor. The band is actually made of volcanic material that has no limestone content.

Down on the Farm

Much like a fruit or nut orchard, a vineyard can produce excellent grapes for decades—even a century—if it's given the proper attention. The growing cycle starts in winter, when the vines are bare and dormant. While the plants rest, the grower works to enrich the soil and repair the trellising system (if there is one) that holds up the vines. This is when pruning takes place to regulate the vine's growth and the upcoming season's crop size.

In spring, the soil is aerated by plowing, and new vines go in. The grower trains established vines so they grow, with or without trellising, in the shape most beneficial for the grapes. Bud break occurs when the first bits of green emerge from the vines, and a pale green veil appears over the winter's gray-black vineyards. A late frost can be devastating at this time of year. Summer brings the flowering of the vines, when clusters of tiny green blossoms appear, and fruit set, when the grapes form from the blossoms. As the vineyards turn luxuriant and leafy, more pruning, along with leaf pulling, keeps foliage in check so the vine directs nutrients to the grapes, and so the sun can reach the fruit. As summer advances, the grower will thin the fruit, cutting off (or "dropping") some bunches so the remaining grapes intensify in flavor. A look at the vineyards reveals heavy clusters of green or purple grapes, some pea-size, others marble-size, depending on the variety.

Fall is the busiest season in the vineyard. Growers and winemakers carefully monitor the ripeness of the grapes, sometimes with equipment that tests sugar and acid levels and sometimes simply by tasting them. As soon as the grapes are ripe, harvest begins amid the lush foliage. In California this generally happens in September and October, but sometimes a bit earlier or later, depending on the type of grape and the climatic conditions. Picking must be done as quickly as possible, within just a day or two, to keep the grapes from passing their peak. Most California grapes are harvested mechanically, but some are picked by hand. After harvest, the vines start to regenerate for the next year.

Sometimes by preference and sometimes by necessity, winemakers don't grow all the grapes they need. Small wineries with only a few acres of grapes are limited in the varietals and quantities they can grow. (The smallest producers don't even have their own wineries, so they pay to use the equipment and storage space at custom crush facilities.) Midsize wineries may aim to get bigger. If they don't invest in acreage, wineries that want to expand production have to buy grapes from independent growers.

Many winemakers purchase at least some of their grapes. Some have negotiated long-term contracts with top growers, buying grapes from the same supplier year after year. This way, the winemaker can control the consistency and quality of the fruit, just as if it came from the winery's own vineyard. Other wineries buy from several growers, and many growers sell to more than one winery.

Winemakers who buy from growers face a paradoxical problem: it's possible to make a wine that's too good and too popular. As the demand for a wine—and its price—rises, so will the price of the grapes used to make it. Other wineries sometimes bid up the price of the grapes, meaning that a winemaker can no longer afford the grapes that made a wine famous. This competitiveness among winemakers for specific batches of grapes underscores the importance of growers.

Organic and Biodynamic

If, as many grape growers insist, a wine is only as good as the vineyard it comes from, those who have adopted organic and biodynamic agricultural methods may be on to something. But when using terms like organic and biodynamic, what do vintners mean? Although organic viticulture is governmentally recognized and regulated, it is vaguely defined and its value is hotly debated—just like the rest of organic farming. It boils down to a rejection of chemical fertilizers, pesticides, and fungicides. Biodynamic farmers also reject these artificial agents, and their vineyard maintenance involves metaphysical principles as well.

Partly because it's difficult and expensive to qualify for official certification, partly because organic vineyards have smaller yields, and partly because it's hard to grow grapes organically except in warm, dry climates, organic viticulture remains the exception rather than the rule, although more vineyards are being certified organic every year.

Even rarer than wines produced from organically grown grapes are completely organic wines. For a wine to be certified as organic, not only do the grapes have to come from organic vineyards, but the processing must use a minimum of chemical additives. Some winemakers argue that it is impossible to make truly fine wine without using additives like sulfur dioxide, an antioxidant that protects the wine's color, aroma, flavor, and longevity.

Many wineries that might qualify as partially organic resist the label, wary of its effect on their reputation. Still, the movement is gaining momentum. Many major players, even if they are not certified organic, have taken steps to reduce their use of pesticides or implement other eco-friendly policies. Others grow some or all of their grapes organically. Very few producers make completely organic wine.

If demand for organic products continues to grow, supply will no doubt follow suit. In the meantime, if you want organic wine, read the label carefully. To be called organic, a wine must contain certified organic grapes and have no added sulfites. (Remember that some wines made from certified organic grapes still contain naturally occurring sulfites.)

Their interest in organic farming has led some winery owners and vineyard managers to adopt biodynamic farming methods. The principles of biodynamic agriculture were conceived in the 1920s by the Austrian scholar and mystic Rudolf Steiner and refined in the 1930s by Ehrenfried Pfeiffer, a German scientist and specialist in soil management.

Biodynamic farmers view the land as a living, self-sustaining organism requiring a healthy, unified ecosystem to thrive. To nurture the soil, for instance, vineyard workers spray specially formulated herbal "teas" (the ingredients include yarrow, dandelion, valerian, and stinging nettle flowers) onto compost spread in the fields. Grazing animals such as sheep or goats maintain the ground cover between the vines (the animals' manure provides natural fertilizer), and natural predators, among them insect-eating bats, control pests that might damage the crop. Steiner and his successors believed that the movements of the sun and the moon influence plant development, so astronomical calendars play a role in the timing of many vineyard activities.

At its most elevated level, the biodynamic philosophy recognizes a farm as a metaphysical entity that requires its human inhabitants not merely to tend it but to form a spiritual bond with it, a notion that other organic farmers share in theory even if their methods sometimes diverge. Among wineries whose practices have been certified organic are Hall in the Napa Valley, and Preston of Dry Creek in Northern Sonoma County. The Napa Valley's Robert Sinskey Vineyards is certified both organic and biodynamic, as is the Sonoma Valley's Benziger Family Winery.

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