英文科學讀本 第六冊·Lesson 49 Beverages—Fermented Drinks

Lesson 49 Beverages—Fermented Drinks

The sweetening principle of all fruits is known as grape-sugar. If the juice is squeezed out of some fruit, and then left to stand for a time in a warm temperature, there is a natural tendency in the grape-sugar which it contains to undergo a remarkable change. During this change the surface of the liquid becomes covered with a film, resembling yeast, and two new substances are formed—alcohol and carbonic acid gas. We speak of the change as fermentation. The presence of the alcohol in the juice can be easily detected by its peculiar, sharp, biting taste.

If the juice were allowed to stand for a sufficient length of time, it would continue to ferment, and more and more of the grape-sugar would be converted into alcohol. The juice would become actual wine. This is the whole secret of fermentation. As the juice ferments, its grape-sugar becomes converted into alcohol.

It is no part of our business to follow up the process of wine-making. Properly speaking, the name wine is generally used in a restricted sense for those drinks made from the fermented juice of the grape, but wine is made from most fruits.

There are many varieties of wine, according to the kind of grape and the mode of preparation. The wine countries of Europe are France, Spain, Portugal, Germany, Italy, Hungary, Greece, and Turkey; and in all these the cultivation of the vine and the manufacture of the grape into wine constitute most important national industries.

From France we get Champagne, Medoc, Burgundy, and Bordeaux. Spain supplies us with Sherry and Malaga; Portugal with Port. The wines of Germany are produced in the basin of the Rhine, and are commonly known as Rhenish wines. Moselle is also a German wine. Madeira, a wine resembling Sherry, comes from the island of that name, and the chief of the Hungarian wines is Tokay.

Some wines are bottled while the fermenting process is going on. They still contain the carbonic acid gas, and it is this gas in the wine which causes it to foam when uncorked, and gives the wine its brisk taste. Such wines are known as sparkling wines. Others are not bottled until the work of fermenting is completed. In the preparation of these wines the carbonic acid gas is allowed to pass off before they are put into the bottle, and they do not continue to work and foam. These are known as still wines.

The total quantity of wines of all kinds imported into this country in the year 1893 was 14,538,048 gallons.

The juices of the apple and pear are fermented, and made into a kind of wine. That made from the apple is called cider; that from the pear is perry.

Most of the palms yield a sweet juice, which if allowed to ferment will produce an alcoholic liquor. Toddy is a kind of wine made from the juice of the topmost spathe or flower-shoot of the coconut palm. It is made and consumed in large quantities in all countries where this palm grows.

A somewhat similar wine is made from the date-palm. It is known as date-wine, and is highly esteemed by the people of the deserts where this tree grows.

You remember that the starches can be made to yield a kind of sugar, called maltose. This starch sugar, like the grape-sugar of fruits, will ferment if dissolved in water, but only after some yeast has been added to the solution.

This constitutes the difference between wines and beers. Wines are made from grape-sugar, which ferments spontaneously; beers are made from sugar, which requires yeast to make it ferment. In both cases the fermentation splits up the sugar into alcohol and carbonic acid gas.

Barley is the usual starch grain for brewing purposes, although maize is rapidly coming into use. The grain is first converted into malt by the maltster. He soaks it in a tank of water for two days, and then lays it out evenly on the floor of the malt-house in a warm temperature. After about a fortnight the grains are seen to be sprouting. They are then in this state thrown into an oven or kiln. The heat stops further growth, and the starch is converted into sugar. In this condition the grain is called malt. We have nothing to do with the process of beer-making. It will be enough for us to know how the barley grain is converted into malt.

Hops are grown largely in this country for the purpose of brewing. They give the beer its bitter aromatic flavor, and also prevent it from turning sour. The hop gardens of England extend into fifteen counties, and occupy no less than 71,789 acres. Kent is the chief county for hops. A hop garden in the flowering season, when the plants are in their beauty, presents a picturesque sight, and is sometimes called the English vineyard.

Spirituous liquors are made by the process of distillation. If a fermented liquid is boiled in a closed vessel, the alcohol which it contains, as well as the water, will assume the vapor form and pass away into the cooler to be condensed. But this will take place only when the boiling point is reached. The boiling point of alcohol is 172°F, that of water 212°F.

In distilling alcoholic liquors, therefore, the aim is to keep the liquid in the boiler at or near the boiling point of the alcohol itself, but below the boiling point of the water. The alcohol vaporizes and passes away into the condenser, and the water is left behind.

In this way wine is distilled and made to yield brandy; fermented molasses is distilled and made to yield rum; and the liquor of malt treated in a similar way gives whisky.

It must be carefully borne in mind that our purpose in dealing with these intoxicating drinks here is merely to point out the materials from which they are made, and to give a general notion of their preparation. We have nothing to do with them in themselves. Whatever good they may have done, it is certain that they have done untold mischief, and that man is wisest who has nothing to do with them.