during about an hour, when the cheese is removed, trimmed, turned, wrapped in cloth, and replaced for the final pressing.

Ripening or curing the cheese. When taken from the press, cheese is said to be unripe, green, or uncured. It must be stored for weeks or months to become properly ripened. The higher the temperature to which cheese is exposed in ripening, the more rapid the process will be, but this is attained usually at the expense of the quality of the cheese. For the best results, the ripening is conducted at a temperature not above 55° F. and requires a comparatively long time. During the ripening the cheese undergoes some loss of weight by evaporation of moisture, but the chief object of the ripening process is to secure certain changes in texture and flavor which depend essentially upon a gradual hydrolysis of the cheese protein, the changes being very similar to those which take place in digestion.

The increase of soluble proteins, and of the products of further cleavage, which takes place at the expense of the insoluble protein of the original curd, is shown in Table 9, which is condensed from data given by Van Slyke and Publow.1

TABLE 9. DEVELOPMENT OF PROTEIN CLEAVAGE PRODUCTS IN CHEESE

AGE OF CHEESE

NITROGEN, EXPRESSED AS PERCENTAGE OF THE TOTAL NITROGEN OF
THE CHEESE, IN THE FORM OF:

Soluble Proteins and Derivatives

Proteoses

Peptones

Amino-acids

Ammonia

The changes which take place in the cheese protein during the ripening process are doubtless due to a combination of factors. Van Slyke holds that (1) the lactic acid, (2) the rennet enzyme, (3) the milk enzyme (galactase), (4) microorganisms, chiefly bacteria, all play important parts in the ripening process. The exact part played by each of these factors is still a subject of investigation.

Other Varieties of Cheese

Since about three fourths of all the cheese used in the United States is of the Cheddar type, only that type can be considered at all fully here. Most of the following statements regarding a few other varieties of cheese are abbreviated from the descriptions given by Doane and Lawson.1

Brie. This is a soft rennet cheese made from cows' milk. The cheese varies in size and also in quality, depending on whether whole or partly skimmed milk is used. The method of manufacture closely resembles that of Camembert.

This cheese has been made in France for several centuries. Mention was made of it as early as 1407. It is made throughout France, but more extensively in the Department of Seine et Marne, in which it doubtless originated. More or less successful imitations of this cheese are made in other countries. It was estimated that 7,000,000 pounds of Brie cheese were sold in Paris during 1900. The export trade is also very important.

Camembert. This is a soft rennet cheese made from cows' milk. A typical cheese is about 4 inches in diameter and 1 inches thick and is usually found on the market in this country wrapped in paper and inclosed in a wooden box of the same shape. The cheese usually has a rind about one eighth of an inch in thickness which is composed of molds and dried cheese. The interior is yellowish in color, and waxy, creamy, or almost fluid in consistency, depending largely upon the degree of ripeness.

1 Varieties of Cheese: Descriptions and Analyses. United States Department of Agriculture, Bureau of Animal Industry, Bulletin 105.

Camembert cheese is said to have originated in 1791 in the locality from which it derives its name in the Department of Orne, in the northwestern part of France. The industry extended soon into Calvados, and these two departments are still the principal seat of the industry. Very successful cheeses of this type have been made at the Storrs Agricultural Experiment Station in Connecticut.

Cheshire. This cheese is one of the oldest and most popular of the English varieties. It is a rennet cheese made from unskimmed cows' milk, and is named for Chester County, England, where it is largely produced. It is made in cylindrical shape from 14 to 16 inches in diameter, and weighs 50 to 70 pounds. In making this cheese sufficient annatto is used to give the product a very high color.

Cheshire-Stilton. This is a combination of the Cheshire and Stilton varieties of cheese in which the general characteristics of size and shape and manufacture of the Cheshire are retained, and a growth of the mold peculiar to Stilton is secured. The mold is propagated by keeping out each day a portion of curd and mixing it with some older curd in which the mold is growing well.

Edam. This is a hard rennet cheese produced in Holland; it is also known as Katzenkopf, Tete de Maure, and Manbollen. The best of the product is made of unskimmed cows' milk, but much of it at the present time is made from milk which has had at least one half of the fat removed. The cheeses are round and are colored deep red on the surface or wrapped in tinfoil.

When the cheese is one month old, it is washed in water at 70° F. for twenty minutes and then placed in the sun to dry, after which it is rubbed with linseed oil. Before shipping the cheese is colored, usually red, but for some markets it is colored yellow with annatto. This coloring is done with a watery solution of litmus and Berlin red, or with carmine. A considerable quantity of this cheese is imported into the United States. At the present time some Edam cheeses are inclosed in air-tight tins for export.

Emmental. This is a hard rennet cheese made from unskimmed cows' milk, and has a mild, somewhat sweetish flavor. It is characterized by holes or eyes which develop to about the size of a half inch in typical cheeses and are situated from 1 to 3 inches apart

Emmental cheese is a very old variety. In the middle of the fifteenth century a cheese probably of this type was manufactured in the Canton of Emmental. In the middle of the seventeenth century the industry was well developed and Emmental cheese as we now know it was being exported. In 1722 its manufacture under the name of Gruyère is recorded in France, two coöperative societies having been organized for this purpose.

Emmental cheese is now manufactured in every civilized country. In the United States its manufacture has recently received an important impetus through the discovery in the Dairy Division of the United States Department of Agriculture, of the organisms responsible for the particular combination of flavor and texture desired.

Gorgonzola. This variety, known also as Stracchino di Gorgonzola, is a rennet Italian cheese made from whole cows' milk. The name is taken from the village of Gorgonzola, near Milan; but very little of this cheese is now made in that immediate locality. The interior of the cheese is mottled or veined with a penicillium much like Roquefort, and for this reason the cheese has been grouped with Roquefort and Stilton varieties. As seen upon the markets in this country, the surface of the cheese is covered with a thin coat resembling clay, said to be prepared by mixing barite or gypsum, lard or tallow, and coloring matter. The cheeses are cylindrical in shape, being about 12 inches in diameter and 6 inches in height, and as marketed are wrapped in paper and packed with straw in wicker baskets.

The manufacture of Gorgonzola cheese is an important industry in Lombardy, where formerly it was carried on princi

pally during the months of September and October, but with the establishment of curing cellars in the Alps, especially near Lecco, the manufacture is no longer confined to this season.

At an early stage in the process of ripening the cheese is usually punched with an instrument about 6 inches long, tapering from a sharp point to a diameter of about one eighth inch at the base. About 150 holes are made in each cheese. This favors the development of the penicillium throughout the interior of the cheese. Well-made cheese may be kept for a year or longer. In the region where made, much of the cheese is consumed while in a fresh condition.

Gruyère. This name is applied to Emmental cheese manufactured in France, the name originating from the Swiss village of Gruyère. The cheese was first mentioned in 1722, when two societies were reported to have been organized for its manufacture. The Gruyère cheese is made in three different qualities - whole milk, partly skimmed, and skimmed. It is usually made from partly skimmed milk, and this is supposed to distinguish it from Emmental, which is supposed to be made from whole milk. The manufacture of Gruyère cheese is an extensive industry in France, about 50,000,000 pounds having been manufactured annually the latter part of the last century.

Limburg. This is a soft rennet cheese made from cows' milk which may contain all of the fat or be partly or entirely skimmed. The best Limburg is undoubtedly made from whole milk. This cheese has a very strong and characteristic odor and taste. The cheese is about 6 by 6 by 3 inches and weighs about 2 pounds.

Limburg cheese originated in the province of Luttich, Belgium, in the neighborhood of Hervé, and was marketed in Limburg, Belgium. Its manufacture has spread to Germany and Austria, where it is very popular, and to the United States, where large quantities are made, mostly in New York and Wisconsin.