Alcohol is produced by yeast fermentation of various plants. Yeasts are single-celled fungi. The genus Saccharomyces is the one most commonly used due to its efficient alcohol production and tolerance of high alcohol levels. Yeasts can break down simple sugars only (monosaccharides) into CO2 and ethanol. So, enzymes that break down starch and dissacharides (sucrose = glucose + fructose is most common sugar in plants) must be added before adding yeast except for honey and some fruit juices.

Yeast can live until alcohol concentration gets up to 18%. To get higher concentrations, solution must be fortified or distilled.

Ethanol is water and fat soluble so it moves rapidly across membranes, virtually all alcohol is absorbed in the stomach and upper intestine. Alcohol can only be removed from system by metabolic breakdown.

Ethanol is a nonselective CNS depressant that affects all of the neurons in the brain and brainstem. Temporary affects are relaxation, disorientation, loss of reason. Permanent affects are malnutrition, brain damage, cirrhosis of the liver, heart problems, cancer, addiction.

18th amendment (Prohibition) was passed in 1920. Problems with enforcement and ability of organized crime to profit from sale of illegal alcohol led to repeal in 1933 (21st amendment).

Alcohol abuse is clearly our most serious drug problem, there are some indications that alcoholism has a genetic basis which means that individuals who have a parent or grandparent that is an alcoholic should probably never drink.


A. Mead - fermented honey and water, sugar in honey is too concentrated for yeasts to grow so it must be diluted. Probably made by early humans by accident initially. Mead is made now by boiling diluted honey and adding nitrogen-containing compounds, then yeast culture. Fermentation process takes 6-8 weeks.

B. Wine - Yeasts are present on fruit skins so fermentation can occur naturally. Wine was probably produced accidentally as long as 10,000 ybp but that is only a guess.


A. History- domesticated in W. Asia 6000 ybp. Grapes contain a lot of fructose. Egyptians used wine for religious ceremonies, wine became popular for common use in Greece 3000-4000 ybp. Vitis vinifera is the wine grape. Europe and N. Africa were world leaders in wine production but U.S., Argentina and Russia have become important factors in world wine markets. Most U.S. production is in California. Rootstocks from North Americans plants are resistant to an insect that attacks the roots, which saved European wine industry in 1850-60. These plants, mostly from Texas, are used as rootstocks on which traditional varieties are grafted. The insect was N.A. in origin.

B. Culture - In the spring, the new sprouts are trained onto trellises, grapes are harvested in summer. It is important that the water available to the vines is controlled in the weeks before harvesting. Lots of rain will result in grapes with lots of water and low sugar. The best wines are made from grapes with high sugar so it is best to grow grapes in a dry climate where irrigation is available so water can be controlled. Soil types can have a major affect on the quality of wine.

C. Processing - Vintage, expensive wines are produced in the old manner but production of bulk wines has been highly automated and is done in large stainless steel tanks.
Grapes are crushed, usually mechanically. Red wines are produced by putting skins in with juice, pigments dissolve in juice. White wines are produced by leaving out the skins. Special strains of yeast are added and the wine goes through a series of aging tanks, the sedimentation of yeasts and acids occurs throughout. Some wines are transferred to wooden casks for aging. Aging reduces acidity and develops flavor. Winemasters taste wine and determine when it is ready to bottle. After bottling, white wines should not be kept for more than 5 years, red wines improve up to 40 years. The above process produces still wines.

Champagne and sparkling wines are produced by adding sugar to wine that still has live yeast and then capping the bottle. Particulate matter must still be removed,which is a tricky process. Sparkling wines are produced by pumping CO2 into still wines and closing bottle.

Fortified wines - Sherry, port and Madeira are produced by mixing wine with high alcohol, Aperitif wines - Dubonnet and vermouth are wine + alcohol + flavorings
Cheap fortified wines are preferred by "winos" - Thunderbird, MD 20-20, Ripple.

C. Beer

Beers have been made for at least 6000 years. Brewing has been a hit and miss process until about 200 years ago, until then it was difficult to control quality. High quality beer has three basic ingredients: barley malt, hops, and water. Adjuncts are used extensively in cheap beers.

Malt - dried sprouted grain of barley (Hordeum vulgare) - contains enzymes which convert starch into monosaccharides. Barley grains are germinated which converts starch to sugar and breaks down proteins to yield amino acids, grain is dried with heat which kills seedlings and microrganisms.

Hops - Humulus lupus - Cannabaceae, dioecious vines, bracts of female flowers contain volatile oils which flavor beer and enzymes which coagulate proteins making a clear liquid.

Adjuncts - alternative starch sources - unmalted grains, corn grits, corn syrup, potatoes, more commonly used in U.S. than in Europe.

BREWING - adjuncts + malt + water = mash, the liquid portion of the mash is wort, wort is boiled, hops are added and removed, wort is sent to fermentation tank and yeast are added. The type of beer produced can be controlled by the strain of yeast and temperature. "Green" beer is allowed to age for 2 to 3 weeks, then is normally pasteurized and filtered and then must be recarbonated. Brewing is much more automated and controlled than wine production.

D. Sake - "rice wine"

Conversion of rice starch to sugar is done by Aspergillus (bread mold). Yeast are then added for fermentation, final alcohol concentration is 19% and is fortified to 20-22%.

E. Chicha - corn beer, Central and S. America, made from chewed corn.

F. Pulque - Agave stems are baked, mashed and mixed with water, distillation of pulque produces tequila and mescal.

G. Distillation
Whiskeys - distilled from "beers" and aged - Scotch, Bourbon, Rye.
Cognacs and brandies - distilled from wines.
Grain alcohol is 95% = 190 proof
Gin and vodka - ethanol + water, gin is flavored.
Rum - fermented molasses or sugarcane juice

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