Wine
is an alcoholic beverage most often made from the juice of grapes. Wine also can be made
from many other fruits, including apples and pears, and even from such plants as
dandelions. Many wines retain the flavor and aroma of the fruit from which they were made.
For thousands of years, people have used wine to complement meals and to celebrate. They
have also used it in cooking and medicine and in religious ceremonies.
Types of wine. Wines can be divided into four categories: (1) table wines, (2) sparkling
wines, (3) fortified wines, and (4) flavored wines. Alcohol makes up from 7 to 14 per cent
of the volume of most wines. But fortified wines have from 18 to 24 per cent.
Table wines are the most commonly produced type of wine. They are most often served with a
meal. They may be grouped by color into red, white, and rose (pink) wines. Crushed grapes
produce a light green or yellow juice. The juice is tinted by contact with grape skins. In
general, red and rose wines are made from red or purple grapes, and white wines from white
grapes. But a type of white wine called blanc de noir is made from red grapes. The grape
skins have little contact with the juice, giving blanc de noir a paler color than rose.
Wine drinkers describe a wine that lacks sweetness as dry. Most red table wines are dry.
But white wines and rose wines range from dry to sweet. Some white wines can be very
sweet.
Sparkling wines, such as the champagne types, contain bubbles of carbon dioxide gas.
People enjoy drinking sparkling wines on festive occasions.
Fortified wines have brandy or wine alcohol added to them. They tend to be sweeter than
most other wines. For this reason, some people prefer to drink fortified wines with
dessert or after a meal, while others choose to drink dry sherry or white port before
dinner. The most popular fortified wines are port and sherry.
Flavored wines contain flavoring substances. For example, vermouth is a white wine
flavored with herbs. Wine coolers are wines flavored with fruit juices. Most flavored
wines are served alone or before a meal.
Where wine comes from. Most of the world's wine comes from grapes belonging to the species
Vitis vinifera, which originated in the Middle East. Vinifera grapes are also known as
European grapes. These grapes thrive in the vineyards of Europe and on the West Coast of
the United States. Vinifera grapes produce their best wine when grown in regions that are
cool but not cold. In the Eastern United States and in Canada, vinifera grapes have been
crossbred with species native to North America, chiefly Vitis labrusca and Vitis riparia.
These hybrid grapes can withstand cold climates better than European grapes can. But in
many cases, hybrid grapes keep some of the flavor of the native grapes.
Grape species are made up of many varieties. In the United States, many wines take the
name of the variety of grapes from which they are principally made. Such wines are often
called varietals. Examples of varietal wines include Cabernet Sauvignon, Chardonnay, and
Pinot Noir. According to U.S. law, a varietal made from vinifera grapes must contain at
least 75 per cent of the variety after which it is named.
Most European wines are classified by the region they come from, such as Burgundy or
Bordeaux in France or the valley of the Rhine River in Germany. Wines called generics
sometimes take the name of a region in Europe, even though they may show little
resemblance to wines from that region. A generic wine is usually a blend of several
varieties of grapes.
Most nations produce some wine. The countries most famous for their wine include France,
Italy, the United States, and Germany. Spain and Portugal also produce well-known wines.
Wines from France are famous because of French growing conditions and winemaking methods.
The country's chief winemaking regions include Bordeaux, in southwestern France; Burgundy,
in east-central France; and Champagne, east of Paris.
In the Bordeaux region, Cabernet Sauvignon and Merlot grapes go into making dry red wines.
White Bordeaux wines come from Semillon and Sauvignon Blanc grapes. Pinot Noir grapes form
the basis of the red wines of Burgundy. White Burgundy wines come from Chardonnay grapes.
Chardonnay and Pinot Noir grapes also form the basis of champagne, a sparkling wine of the
Champagne region.
Wines from Italy. Grapevines grow throughout Italy. The red wines of the Piedmont region
in northwestern Italy are known as Barolo and Barbaresco. They come from Nebbiolo grapes.
Cortese grapes, also grown in the region, produce a crisp white wine called Gavi. Chianti,
probably the most familiar Italian wine, comes mainly from Sangiovese grapes native to the
regions of Tuscany and Umbria in central Italy.
Wines from the United States. California produces about 90 per cent of the wine made in
the United States. New York, Washington, Oregon, Virginia, and several other states also
make wine. California wines are made from the same varieties of vinifera grapes as are
European wines. California's chief grape-growing regions include the Napa and Sonoma
valleys north of San Francisco Bay; the central coast; and the San Joaquin Valley, in the
middle of the state.
Wines from Germany. Germany's distinctive white wines are produced mainly from Riesling
grapes. Sylvaner grapes are also used to make white wine. Riesling and Sylvaner wines come
from all of the country's winemaking regions, particularly those along the Rhine, Moselle
(or Mosel), and Nahe rivers.
Wine styles from other countries include port and sherry. Port is a fortified wine that
may be dark red or white. It was first made from grapes grown in the Douro Valley in
northern Portugal. Sherry, a fortified white wine, ranges from pale gold to brown and from
dry to sweet. The first sherry wines came from grapes grown in Jerez in southwestern
Spain.
How wine is made. Winemaking requires a series of steps. Decisions made by the winemaker
during each step influence the final "character" of the wine. A winemaker must
first decide which grapes to use and when to harvest them. After the grapes are crushed,
the juice is converted into wine through a process called fermentation. Wine is then aged
until it is ready for drinking.
Harvesting the grapes. Grape growers harvest their crop as soon as the grapes have
ripened, usually in the fall. Winemakers commonly measure ripeness by the amount of sugar
in the grapes. They may also consider the grapes' acid content, flavor, and aroma. Workers
pick grapes by hand or with mechanical harvesters that shake the fruit from the vine. The
grapes then go to the winery for processing. The grape harvest is sometimes called the
vintage. In some years, a favorable climate produces grapes of especially high quality.
Those vintage years are considered superior.
Preparing the juice. At the winery, a machine called a crusher breaks the grapes and
removes them from their stems. The crushed grapes and their juice are called must. The
length of contact between the juice and the skin affects the color of red wines and the
taste of all wines. To make white wine, winemakers separate the skins and pulp from the
juice. The juice then enters a tank or barrel for fermentation. In making red wine, the
seeds and skins go into the fermentation tank with the juice. Stirring the mixture from
time to time ensures that the color is extracted from the skins.
Fermentation is the chemical change in which yeast converts the sugar in grapes into
alcohol. Some yeast grows naturally on the skins of grapes. Some European winemakers allow
this yeast to conduct the fermentation. In the United States and most other countries,
winemakers add selected yeasts to the must to begin fermentation. During fermentation, the
yeast grows and changes sugars called glucose and fructose into ethanol, a type of
alcohol, and carbon dioxide gas. The carbon dioxide is released as bubbles. The yeast also
produces various by-products that may add to the wine's flavor and aroma.
Fermentation also releases heat. Most wineries refrigerate the must to keep its
temperature constant during fermentation. Winemakers usually ferment juice for white wine
at about 59 °F (15 °C) and juice for red wine at about 86 °F (30 °C). The temperature
of the must influences the rate of fermentation, the retaining of grape aromas, and the
formation of yeast by-products. It also determines the rate at which the color and flavor
of the grape skins transfer into the wine. The fermentation of red wine takes from 4 to 6
days. White-wine fermentations last from 12 to 18 days.
Most red table wines and some white table wines undergo a second fermentation, by
bacteria. This fermentation, called the malolactic fermentation, lowers a wine's acid
content by converting a substance called malic acid into lactic acid.
Clarifying and aging the wine. A new wine appears cloudy after fermentation. Winemakers
clarify (clear) the wine by removing particles of yeast and other unwanted substances.
Such particles may be filtered out, allowed to settle naturally, or separated from the
wine by a machine called a centrifuge. Wine may be further clarified, or fined, by adding
certain solutions that reduce the content of unstable or unpleasant components.
After clarification, wine goes into wooden barrels or stainless steel tanks for aging.
Wooden barrels contribute their own flavor to the wine. The size of the barrel, the age of
the wood, the storage temperature and humidity, and the length of storage time all
influence the extent of the aging process. Many wineries hold wine at a temperature close
to freezing for one or more days so that a salt called potassium bitartrate will
precipitate (separate) out of the wine. This prevents the salt from forming crystals in
the wine after bottling.
Although some wines are soon ready for drinking, others must age a few years to soften
harsh flavors and allow desirable flavors to develop. Wine is bottled after some aging,
and it continues to age slowly in the bottle.
Fortified wines, such as port and sherry, are made by adding brandy to fermenting must.
The brandy halts the fermentation by killing the yeast before all the sugar has turned
into alcohol. The wine that results generally is sweet. Drier fortified wines are achieved
by adding brandy near or at the end of fermentation. Sparkling wines are usually made by a
second yeast fermentation of a table wine. This fermentation may take four to eight weeks.
The bubbles of carbon dioxide produced by the fermentation are trapped in the wine.
History. The earliest references to wine date back about 5,000 years to civilizations in
ancient Egypt and Babylon (now part of Iraq). Egyptian picture writing shows people
harvesting and crushing grapes and storing wine in clay vessels. The Bible tells of
winemaking in Canaan (later called Palestine). The ancient Greeks and Romans dealt
extensively with wine in their paintings and writings. The Romans planted grapevines in
regions they conquered, including what are now Austria, France, and Germany.
From about A.D. 500 to 1400, the spread of Christianity in Europe encouraged the growing
of grapes to make the wines used in religious ceremonies. After the 1500's, European
explorers and settlers introduced vinifera grapes to the lands now known as Argentina,
Australia, Brazil, Chile, Mexico, New Zealand, South Africa, and the United States.
Contributor: Roger Boulton, Ph.D., Prof. of Enology, Univ. of
California, Davis. |
