Climate Change: Controversial or not, climate change is having a profound effect on the world’s vineyards, especially in Europe, where the boundary for wine growing moves steadily northward. The vineyards of Burgundy, which have always been vulnerable to cold winters resulting in poor harvests, have enjoyed an unprecedented twenty years of perfect growing seasons. The worry is that eventually, as the climate warms, it will become too hot for the Pinot Noir and Chardonnays, which also need cool evenings in order to produce that Burgundian magic. In Germany, too, with the extra sunshine, the Riesling grapes are producing more sugar, and thus the Auslese wines of the Moselle are becoming sweeter and more alcoholic.
The main beneficiaries of climate change are the English, who are finally able to grow their own vines and make their own wine without being beholden to any beastly foreigners. Various French Champagne houses are actually buying land in Southern England and planting vineyards in the same chalky, limestone soil they are used to back home in Northern France. The area of vines planted in England and Wales has doubled from 761 hectares in 2004 to about 1,500 hectares in 2013. The country now has almost 500 vineyards, and English “champagnes” are winning international prizes and being compared favorably—even by the French—to the best French Champagnes. In 1998, an English Classic Cuvée 1993, won first prize at the International Wine & Spirit Competition and was voted best sparkling wine in the world.
Varietal: Varietal refers to the specific type of grape, each of which has different requirements and produce different types of wine. Some varietals need more rain while others need more sun. Some varietals require a longer growing season, some bud early in the year, others reach fruition later. Over the centuries, winegrowers have matched the different varieties of grape with the ideal climate, elevation, and soil type. In Europe, with over 2,000 years of experience, different regions have their own specific grape varietal; in Burgundy, all red wines are made from the Pinot Noir grape, while in Tuscany all red wines are made with the Sangiovese grape. (The major different varietals are described alphabetically starting in Chapter Six.)
Vintner: The vintner, or winemaker, is the person whose decisions affect the final quality of the wine. Until recently, the vintner would rely on tradition, using the wisdom and experience passed down from his father and grandfather who had typically been producing wine in the same place for generations. These days, the vintner is probably university-trained and bases his decisions on the latest scientific research. Another major difference is that these days, the vintner is very often female, as more and more women are running vineyards and directing wineries. Today, there are even “Flying Winemakers” who travel the world, sharing their expertise for the week or two they spend visiting different vineyards and wineries on their travels.
Viticulture: How Vines are Grown (Sun + grape = sugar)
The Vine: The vine is nature’s factory that produces the sugar out of earth, air, sun and water which the vintner will ultimately use to make wine. The roots of the vine pull water out of the earth, while the chlorophyll in the green leaves draws carbon dioxide out of the surrounding air. By the magical process of photosynthesis, light from the sun transforms these simple ingredients into sucrose sugars. The rising sap then takes this sucrose into the flesh of the grapes, which is used to provide the seeds with energy. This whole cycle has no other purpose than to provide the seeds with enough food and vigor to start the next generation. The production of juicy grapes or fine wines is purely incidental to Nature, whose only interest lies in propagating the endless cycle of birth and rebirth.
Winter Dormancy: Following the harvest in the fall, the vines are pruned of all signs of life and are left to survive the harshness of the winter on the bare ground. Unlike the luxuriant green plant of high summer, the vine in winter resembles an unattractive piece of dead driftwood. During the winter months, the vine becomes entirely dormant and all the sap descends deep underground to protect the roots. During the growing season, a vine will be destroyed if the temperature falls below 27° F. But during the winter with the sap protecting the roots, the vines can survive temperatures as low as minus 5°F.
Frosts: The vinegrower’s year is bookended by the last frost of the spring and the first frost of the fall. If the vines are allowed to bud before winter’s final frost, they will not survive. Similarly, if the grapes are not picked before the first frost of the fall, the whole harvest could be ruined. The challenge for the winegrower is to maximize his growing season between those two frosts. The more days of sunshine to which the growing vines are exposed, the more sugar will be produced, and thus the higher alcohol level in the wine.
Vitis vinifera
Month
Weather
Vine
Vineyard Work
Cellar work
January
Malolactic Fermentation
February
Weeping
Pruning
Topping-up / ullage
March
Spring Frost
Bud Break
Frost protection
Bottling
April
Shooting
De-suckering
Racking
May
Flowering
Shoot postioning
Assemble & ship orders
June
Fruiting
Binal racking of good wine
July
Summer Sun
Veraison
Spraying (disease)
Bottling older wines
August
Ripening
Thining grapes
Clear for Vendage
September
Vendage (harvest)
Vendage
October
Fall Frost
Passerillage
Late harvest
Fermenting
November
Botrytis Cinerea
Late harvest
Fining / racking
December
pruning
taste new wines/ malolactic fermentation
Figure 1: The Year of the Vine
Weeping: As winter ends, the ground temperature rises, and once the vine senses the first stirring of spring in the air, it slowly returns to life. As the temperature one foot beneath the surface reaches about 50°F, by a process of osmosis, the sap starts rising from the roots deep in the earth and spontaneously begins to drip from the cuts where the vine was pruned the previous season. It is a beautiful and moving precursor of spring when a whole vineyard begins to glisten with the rising sap, a sign that the cycle of life will begin anew. This natural phenomenon is called “weeping” or “bleeding,” and each individual vine is capable of weeping eleven pints of sap.
Bud Break: Within twenty or thirty days of weeping, the first buds begin to form, which means that the vine is at its most vulnerable to late frosts. This is the time of year when the farmer is out in the vineyard, sometimes all
night, lighting fires, using smudge-pots, covering the vines, spraying water, blowing fans, or even using the downdraft from helicopters—whatever will best protect the delicate young buds from the damaging frost. An early bud-break is obviously vulnerable to frost, but a late bud-break might mean the grapes will not have a long enough growing season in order to ripen.
Shooting: As the buds produce shoots, these need to be trained onto the trellises which will permit them to spread and support the bunches of grapes. Depending on the grape variety and the wine region, different trellis systems are used; some have just a single strand of wire, while other systems—typically exposed to more sun—allow for several strands, supporting a denser concentration of fruit and a thicker, protective covering of leaves. Buds which do not quickly produce shoots are removed by the farmer in a process called de-suckering, so that only the healthiest buds survive.
In many wine regions, especially in France where the Appellation laws are most strict, there are limits governing how many shoots or buds are permitted on specific vines, and the local “wine police” will inspect vineyards to ensure that the farmer has pruned or de-suckered correctly. The purpose of this is to ensure quality. The less buds and shoots means less grapes and less juice, but also results in a higher concentration of taste—thus ensuring the continuing reputation of the Appellation.
Flowering: Approximately another month or more after the bud-break, the first flowers appear on the end of the shoots as clusters of tiny “buttons.” Within a couple of weeks these small buttons grow to become small berries which, being hermaphroditic, immediately begin to self-pollinate. During the pollinating period the vine is very sensitive to outside influences, such as climate and temperature, and, depending on the health of the vine, as little as 30 percent or as much as 60 percent of the flowers may successfully pollinate, producing fruit.
Fruit Set: Following pollination, the berries quickly grow into what are now recognizable grapes, filling with acidic flesh and developing skins with yeasts and tannins. It is at this point, depending on the success rate of the pollination that the farmer can begin to predict the potential harvest crop yield. As spring advances to summer, the chlorophyll in the leaves of the vine start to absorb the light from the sun and, by photosynthesis, to convert the carbon dioxide in the surrounding air into pure energy, which in turn magically converts the flesh of the grape into sugar. The sugar has two purposes: to feed the seed with energy and to make the grape sweet and attractive to birds and animals so they will carry the seeds to a new location to start a new generation.
Veraison: This French term means the beginning of ripening, when the grapes change color as the natural acids in the flesh hydrolyze the sucrose into glucose and fructose to feed the pip with energy to become the seed for a new generation. With veraison, the skin of red grapes becomes darker in color while the skin of white grapes becomes more translucent. At the same time as the skin changes color, the fruit acidity decreases and the sugar level increases by as much as 25 percent. Veraison signifies that the seed of the grape has reached maturity, and as the grape grows fleshier, sweeter, and less acidic, it is obviously more attractive to animals, who, by eating the fruit of the vine, ultimately spread the seeds.
Vendange/ Harvesting: Harvesting traditionally takes place one hundred days after flowering; in the northern hemisphere this occurs between August and October (and between February and April south of the equator). In addition to the latitude of the vineyard and the variety of grape to be picked, the decision of when exactly to begin the harvest depends on the weather and the balance of acid and sugar within the grape. In addition to the sugar/acid balance, the farmer will be judging the taste of the grape to decide if the tannins have begun to ripen and soften. Traditionally, the farmer would make his decision by tasting the grapes on a daily basis, but increasingly these decisions are also being confirmed in the laboratory when random samples of grapes are tested for the correct balance of pH levels and acidity. Typically, a wine-lab will seek a reading of 19-25 degrees Brix, over 0.7 percent acidity and with a pH of less than 3.4. (One degree Brix represents 1 gram of sucrose in 100 grams of liquid juice). The grape is considered ripe when the sugar stops increasing and the acid stops decreasing.
Vineyard Yield: Depending on the size of the grape, about 700 grapes are needed to make one bottle of wine. Different growing regions have different rules concerning the amount of grapes per acre that can be harvested or how much wine can be produced per acre. On average, depending on local rules and conditions, one ton of grapes will produce about 150 gallons of wine, which is about sixty cases, or 720 bottles of wine. Obviously, growing conditions vary enormously around the world, from the rich, condensed vineyards of California’s Central Valley to the dry and arid fields of Central Spain where the vines have to be spaced far apart. Consequently, it is much more difficult to discuss average yield per acre when such yields can vary between two tons per acre to ten tons. However, using a conservative four tons per acre, which would result in 600 gallons of wine per acre, or 240 cases, almost 3,000 bottles per acre.
In general, the following can be used for rough calculations:
One bottle of wine = 750 ml or one-fifth of a gallon
One Barrel = sixty gallons or twenty-five cases or 300 750 ml bottles
One Ton of Grapes = approximately sixty cases or 720 bottles of wine
One Acre of Vineyards – Low yield for high quality wines = two tons
One Acre of Vineyards – High yield for less expensive wines = ten tons
One ton of grapes at $1,000 per ton will produce $10 retail bottles of wine (1 percent rule of thumb)
In Bordeaux, for example, the permitted yield for red wine is 588 gallons of wine per acre (fifty-five hectoliters per hectare), or slightly less than four tons of grapes or 240 cases of wine per acre. For Chianti Classico, the permitted yield is more restricted; 52.5 hectoliters per hectare, or about 228 cases per acre. For the sweet white wines of Sauternes and Monbazillac, the maximum yield is even more restricted, with twenty-five hectolitres per hectare or 1.5 tons (ninety cases) per acre.
In California’s Central Valley, the very efficient and mechanized vineyards produce ten tons of Cabernet Sauvignon per acre, which can sell for about $450 per ton (and eventually $4.50 per bottle using the 1 percent rule of thumb). The same grape grown in the Napa Valley, often using old vines and manual labor, tightly pruned to produce less but better grapes, may yield as little as two tons per acre but which will sell for $4,500 per ton (and eventually $45 per bottle).
Early Frost: Just as a late frost in spring can destroy the budding vines and ruin a growing season before it even begins, so too an early frost during the fall can destroy overnight the whole year’s work if the farmer leaves the harvest too late. In choosing when to harvest, the farmer must be thinking of potential frosts as well as the ripeness of the grape. However, certain white wines are deliberately left on the vine, even after the frost, to create a powerful and sweet “late harvest” wine.
Late Harvest Wines:
Passerillage: If picking is delayed and the grapes are left on the vine after the regular harvest has finished, the vine leaves turn yellow and the stems turn woody while the sap stops rising and remains deep below ground to protect the roots through the cold winter months. With no sap rising to nourish the grapes, they shrivel and dehydrate. As the sugar content becomes more concentrated, the flesh of the grape experiences complex chemical changes which adds to the rich taste of the eventual wine. Alternatively, the grapes are placed on straw mats after being picked and allowed to dry in the sun. In Northeast Italy this form of passerillage is called appassimento.
Botrytis cinerea (noble rot), similar to passerillage, is actually a fungal infection called Botrytis cinerea (or more correctly, if not more improperly, Botryotinia fuckeliana, named in honor of a nineteenth century botanist named Karl Wilhelm Gottlieb Leopold Fuckel). This fungal pathogen colonizes gra
pes in order to glean nutrients from them. The infected pathogens produce the enzymes laccase and pectinase, which help the fungus break down the skin of the grapes to gain access to the inside of the fruit. Botrytis, like most molds, enjoys a humid environment, and in the Sauternes region south of Bordeaux, for example, weather conditions are very specific—with humid, cool mornings and warm, sunny, and dry afternoons—which keep the infection from growing too rapidly and turning into sour rot.
Noble rot uses the pectinase enzymes to break through the skin of healthy grapes, which leads to a natural dehydration of the fruit since the pectins in the skin are what hold in the moisture. This natural dehydration concentrates the sugars, acids, and flavors within the skins, which are then translated into a more concentrated must during the fermentation. Noble rot adds its own influences in the form of additional flavors of marmalade, quince, and mushrooms.
Noble rot also produces gluconic acid, which increases the acid content of the must. It contributes higher glycerol content, leading to a fuller mouth-feel than the fruit would have had without the infection. These traits are particularly desirable for Sauternes, where the tiny, cool Ciron River meets the larger, warmer Garonne, making for cool, foggy mornings and warm, sunny afternoons. The vineyards in this area maximize their exposure to the fungus through multiple picking times (called tries), during which they only choose the most-affected grapes and leave the less-affected ones to increase in concentration. Because the fungus travels through the vines at an unpredictable rate, the grapes have to be harvested carefully, bunch by bunch, when they are ready. For the very best wines, the grapes are harvested grape by individual grape in the early morning before the heat of the sun can affect them. The best and most famous examples of this process are found in the Sauternes and Barsac regions just south of Bordeaux.
The Booklovers' Guide to Wine Page 5