242 PLANTS AND MAN 



and color, according to the type of grapes used, the length of 

 time that fermentation is carried on, and the locality and season 

 in which they were produced. All are produced by the action of 

 wild yeasts, which occur on the fruit skins, upon the sugar con- 

 tained in the fruit. In using the sugar for its growth and multipli- 

 cation the yeast plant changes it into alcohol, with the liberation 

 of carbon dioxide gas. If wines are bottled while this process is 

 still going on, they produce an effervescence when opened, and 

 are known as sparkling wines, in contrast to the still wines in 

 which the fermentation has been stopped before they are bottled. 

 Naturally fermented wines vary between 7% and 15% in their 

 alcohol content; wines with a higher content have been fortified 

 with brandy or alcohol, since the yeasts are killed or rendered 

 inactive by alcohol in concentrations above 15%. France is the 

 chief wine producing country of the world, with its famed 

 Champagnes, burgundies, Bordeaux wines, and many other 

 kinds known all over the earth. Germany, Italy, Spain, and 

 Portugal also produce widely known wines. The United States is 

 fast developing into a first rank wine producing nation (fig. 170), 

 most of these, however, being consumed within the country. 

 California, New York, Ohio, and Virginia lead in the production 

 of domestic wines. 



Beer has been a popular fermented beverage ever since the 

 Middle Ages. The early beers were of a dark, muddy color, and it 

 was not until about one hundred years ago that the German 

 beers, lighter in color as well as alcoholic content, replaced these. 

 Present day beer is made by "malting" a grain — generally 

 barley — which consists of soaking it in water for one to four days, 

 then spreading it out to begin germination, which converts the 

 starch into sugar due to the activity of the enzyme diastase. At the 

 proper stage of germination, the malt is dried, then ground, 

 mixed with water to dissolve out the sugar, and the liquid portion 

 drawn ofi*. This is boiled with hops to give it the characteristic 

 flavor and improve its keeping qualities, after which the mixture 

 is fermented to the desired stage by the addition of yeast. After 

 straining to remove sediments, the beer is stored in casks or 

 bottles, where a slight fermentation continues, resulting in the 

 carbon dioxide content which causes the liquid to foam when it is 



