Wine is the oldest fermented beverage on the planet.
Wine is produced by the fermentation of fruit juice.
Wine has comforted humans for 10,000 years, dating back to its origins in the Middle East.
It was this cradle of theological thought, this center of the religious universe now threatening Armageddon, where people invented the use and abuse of wine.
It was their drug of choice, after religion that is.
Wine spread from the Middle East by the Romans. The Romans taught Greek medicine and winemaking to the peoples of the countries it conquered.
The Moselle valley of France, the Rhine in Germany, the Danube River valley of Austria and all of Italy became centers for the production of wine because it was the social lubricant of choice in the Roman Empire. Columbus would eventually bring grape cultivation to America while other explorers transported it to Mexico, South America, South Africa, Australia, and California.
The visual and flavor appeal of wine is due to its pigmented molecules. The pleasurable effects are provided by the alcohol molecule.
Wine was and still is, a respite from the harshness and boredom of life. The use of a glass of wine to promote a restful sleep is the oldest form of self-medication known.
The properties of wine are based on their bindings with various receptors. The sensations perceived in the brain are the result of the taste and smell receptors binding with the phytochemicals of the grape. Whereas their effects are based on the alcohol in wine binding to GABA receptors in the brain.
Wines are made from fruits other than grapes. Apples, pears, cherries and berries are fermented to create wines. They all contain about 12 percent alcohol. When fortified with brandy, a wine’s alcohol content can be increased to 20 percent.
Chemistry of Wine
Wine contains a library of plant compounds that protect human health. Most notable is its effect on the heart and the improved lipid profie of thhe blood. These compounds are the plant’s antioxidants. Some of them prevent circulating lipoproteins (cholesterol) from receiving oxidative damage.
In the plant, their role is in protecting the grape from exposure to the sun. The sunlight provides both the energy that fuels the plant’s life as well as the harmful rays that will injure it.
And as occurs in humans, these injuries are the result of free radical attack. These antioxidants protect drinkers of wine by preventing the formation of harmful oxidized cholesterol compounds.
Most of the antioxidant activity of wine is due to compounds that belong in in the catechin family of flavonoids. They are classified as phenolic antioxidants.
Phenolic compounds are believed responsible for the healthy hearts of the French.
Procyanidins are another class of antioxidants present in wine. Procyanidins also inhibit platelet aggregation and sticking.
Grape antioxidants inhibit the copper-catalyzed oxidation of LDL (lousy-cholesterol). By protecting LDL from being converted to the really lousy cholesterol (VLDL), blood dynamics are enhanced. Other phytochemical present in wine include the viniferins, which are potent antifungal agents. The antioxidant effects of red wine is due to the arsenal of polyphenols like catechin, quercetin, and resveratrol. They are also believed to promote nitric oxide production by vascular endothelium. Other effects include the inhibition of thromboxane synthesis in platelets and reduced leukotriene formation in neutrophils.
These compounds are beneficial to human health but because the delivery system includes alcohol, this effect is negated by alcohol addiction.
Yeast (Saccharomyces cerevisiae), the same yeast used in beer and bread making, is added to wine to convert sugar to alcohol. Other yeast strains are used during different stages of the fermentation process. Fermentation occurs in hermetically pressure-sealed containers. The lack of oxygen is required to prevent the oxidation of a wine’s phytochemicals. The airless vats also repress the growth of vinegar-forming, aerobic bacteria.
During fermentation, the fruit of the grape releases its flavor molecules into the wine while and the anthocyanidin pigments contained in the grapes skins provides wine with its color. If fermentation is complete dry wines are produced. If fermentation is incomplete sweet or semi-sweet wines result depending on the amount of residual sugar.
Fermentation and Winemaking
Enology is the study of wine and winemaking.
Wine production involves collecting and crushing ripened grapes and allowing the mixture to naturally ferment and age.
The natural conversion of sugar to alcohol results in a wine that is about 10% alcohol.
Wines can have sugar and yeast added to stimulate a second fermentation to produce CO2. Carbon dioxide gives a sparkling wine like Champagne its bubbly effervescence.
The quality and distinctness of a wine is dependent on the grape used as well as the soil, topography and climate that the grape was grown in.
Winemaking begins with the harvesting and crushing of grapes. The juice that is extracted from the fruit, together with the crushed grapesm is called the ‘must’.
The ‘must’ then undergoes fermentation. Fermentation converts the grape sugars into ethyl alcohol.
Once harvesting is complete and the grapes have been crushed, sulfur dioxide is added. This is needed to suppress the growth of wild yeasts and other organisms that are naturally found in the vineyard. This can also be accomplished with heat.
Depending on the wine, the juice may be separated from the skins before fermentation begins. This is needed when the winemaker wants to prevent skin pigments from becoming part of the wine.
In red-wine production the skins, seeds, and juice are all fermented together.
Fermentation is the process of converting these sugars into molecules of ethyl alcohol and carbon dioxide. The more time the grapes are allowed to remain on the vine, the higher the their sugar content.
Fermentation lasts between ten and thirty days. Malolactic fermentation is a second fermentation process that follows immediately after the first. Anaerobic bacteria instead of yeast convert the malic acid in the grape into lactic acid.
Lactic acid lends a sweeter, less sour flavor to the wine and is necessary to ‘round’ out the flavor of red wines. Since it produces a wine that is less acidic, malolactic fermentation is avoided on white wines because it is the acidity of white wines that provides its pleasant taste.
After fermentation, the wine is separated from its sediment. The sediment or lees is composed of dead yeast cells. Suspended particles give wine a haze and must be removed by clarification. Yeast cells must be removed to prevent fermentation from beginning again after the wine is bottled.
Wine is aged in oak or redwood containers. Aging involves oxygen entering and carbon dioxide exiting through the pores in the wood. This allows yeast to utilize the sugar to multiply and not to convert it into alcohol. This is known as breathing.
When water, carbon dioxide, and alcohol are removed, the acidity of the wine decreases and the phytochemical present in the wine form smaller compounds.
These smaller compounds enhance flavor and aroma.
The wood from the containers also contributes flavor. The wood-aging process may last many months or several years, depending on the wine.
Before bottling, wine may require clarification, blending, filtration, and the addition of an antiseptic agent to prevent microbe development.
Some wines are aged in bottles. Red wines especially may benefit from two to twenty years of bottle aging.