Certain varieties of hard cheese of foreign origin are now made to some extent in this country. If not manufactured in sufficient quantities to supply the demand, the remainder is imported. These hard cheeses are now considered.

SWISS CHEESE

Swiss cheese, variously known as GruyÈre, Emmenthal, Schweitzer and Swiss, had its origin in the Alpine cantons of Switzerland. From this region its manufacture has been carried by Swiss dairy-men and emigrant farmers into widely separate lands. The Swiss colonies settled in the United States in the Mohawk Valley and in Cattaraugus County, New York; in Wayne, Stark, Summit, Columbiana and Tuscarawas counties of Ohio, and in Green and Dodge counties in Wisconsin. Of all these, the Wisconsin colonies have become the most extensive. Similar colonies have developed the making of this type of cheese in Sweden and Finland.

266. The Swiss factory.—Swiss cheese cannot be made in a vat like other types for reasons that will be explained later. In place of the vat is used a kettle, generally of copper, and it may or may not be jacketed for steam or for hot water (Fig. 56). These kettles vary in capacity from 600 to 3000 pounds of milk. The cheese-maker takes the best care possible of his kettle, for an unclean utensil is one of the easiest sources of contamination of the milk. When the kettle is not jacketed, and it is only in recent years that this has been done, it is Swiss-cheese kettle. Fig. 56.—Swiss-cheese kettle. suspended in a fireplace by means of a crane arrangement.

This fireplace uses wood, and is built of brick or stone, so that the kettle rests on the edge and is provided with a door which swings upon another crane, and can be closed while the fire is going. When the kettle is swung on a crane, it is possible to swing it under the weigh-stand for filling. This requires a lid to swing down over the fire, and keep the room free from smoke. The chimney generally has a rather high stack to secure a good draft. This kettle is fastened to the crane by a large iron band passing around the neck, to which a bail or handle is attached. The kettle may be raised or lowered by means of a simple screw on this beam. The crane consists of a heavy beam working in sockets in the floor and a beam or cross brace, which has another and shorter beam braced to it, to take the weight of the kettle.

The weigh-stand, and its efficient location, is a matter of extreme importance. It is elevated a little above the remainder of the floor to allow gravity to do the work. The next most important equipment is the press and draining table. The table is made of wood or stone, and has a slight slope to allow the whey to drain off. The press is generally a jack screw which, braced against a beam, will exert an enormous pressure on the table below.

Swiss cheeses are made in two styles, the "round" or drum and the "block" or rectangular forms, each of which has its advantages. For the round style, which is most commonly made, the forms for hooping are of metal or of elm wood, and consist of strips of a given width, generally six inches, but of an undetermined length. These strips are then made into a circle and held by a cord, which is easily lengthened or shortened, thus varying the diameter of the hoop.

Besides these hoops, cheese boards or followers are needed. These are heavy circular boards, of a size to fit that of the cheese generally made, and are banded with iron around the edge and cross-braced on the bottom for rigidity. The small tools of the factory consist of knives to cut the curd, and of a "Swiss harp" or other similar tool to stir the curd. Many clean bandages are also needed, and a kettle brake.

267. The milk.—Swiss cheese requires clean sweet milk. Dirt, high acid and infections with undesirable bacteria involve difficulties of manufacture and frequent losses of cheese. One common practice rejects milk if it shows acidity above 0.15 per cent. To secure milk in this condition, factories are small and located so close to the producing farms as to secure 1000 to 3000 pounds of milk delivered warm from the cow twice a day. The cheese is made twice daily from this fresh milk. If, however, milk is properly cared for, it is possible to mix night's and morning's milk without bad results. In fact, in working experimentally with high grade milk and taking precautions against loss of fat, it has been necessary to skim (separate) part of the milk, thus reducing the ratio of fat to casein. Analysis of good Swiss cheeses shows that the desired texture is more uniformly obtained with milk in which the fat is less than the normal ratio. This assumes that the manufacturing loss is kept down so that the fat removed offsets the extra loss from curd-breaking.

268. Rennet extract.—Most Swiss cheese-makers prefer to make their own rennet extract from the stomach. This results in a product which is not uniform in strength and so requires good judgment to secure the desired coagulation in the allotted time. Some cheese-makers roll fifteen to twenty well salted calves' stomachs together and dry them. From this they cut off a definite amount each day to be soaked for twenty-four hours in two to five quarts of whey at 86° F. Four quarts of this solution added to 2000 pounds of milk at 90° F. should produce a curd ready for cutting in twenty to thirty minutes.

269. Starter.—Makers do not agree as to the use of "starters" for Swiss cheese. Those opposed to such use say that a starter will give the cheese a decided Cheddar flavor, while those in favor of it state that it will control undesirable fermentations, and that, with the use of a starter, it is possible to make Swiss cheese throughout the year, and have uniform success.

Doane,122 working with Bacillus Bulgaricus as a starter, found that these starters did not always overcome the undesirable fermentations. If a cheese-maker is having difficulty to develop the holes or "eyes," this may be overcome by making a starter123 as follows from good cheese and whey or milk: Select a cheese which has the desirable "eyes" or holes and a good flavor. Grind up some of this and add about ¼ of a pound to one gallon of milk or whey. Hold this for twenty-four hours at a warm temperature (85° to 90° F.). Strain it into the vat of milk just before the rennet is added.

270. The making process.—The milk is delivered twice a day without cooling. It usually reaches the factory at a temperature of 92° to 96° F. It is strained into the kettle, and starter and rennet added at the same temperature as received. (For method of adding rennet, see Chapter V.) Enough rennet should be used to give a coagulation ready for cutting in twenty to thirty minutes. The firmness of the curd is tested by inserting the index finger in an oblique position, then raising it slightly and with the thumb of the same hand starting the curd to break or crack. When the curd is coagulated ready for cutting, it will give a clear break over the finger.

It is important to keep the temperature uniform while coagulation is in process, and this is best accomplished by the use of a little pan arrangement which fits into the top of the kettle. When this is full of water at 100° F., the temperature of the air above the milk will be about 90° F. When the curd is ready for cutting, a scoop may be used and the top layer carefully turned under to equalize the temperature more closely.

Cutting the curd.—In some cheese factories, knives resembling Cheddar cheese knives are employed to cut the curd. In other factories, a "Swiss harp" is used to break the curd. The curd is usually cut or broken into pieces about the size of kernels of corn. The practice of "breaking" curd instead of cutting it with sharp curd-knives produces excessive loss at times. Experimental study has shown that the loss of fat may be kept as low as 0.3 per cent if modern curd-knives are substituted for the breaking tool formerly used. Study of Swiss cheeses of all grades supports the opinion that the removal of a small part of fat from usual grades of factory milk produces a better quality of product than the use of rich whole milk. This may be accomplished through the escape of fat in the whey on account of breaking the curd and stirring it vigorously, or by skimming a part of the milk which is then curdled, cut and stirred under such conditions as to minimize the loss of fat.

Cooking the curd.—After cutting, the curd is stirred in the whey for about twenty minutes before the steam is turned on and is then heated to 128° to 135° F. While this heating is in progress, constant stirring must be given to avoid matting. This excessive stirring breaks the curd up into pieces about the size of wheat kernels, and accounts for the large fat loss, which is one of the main sources of loss in making Swiss cheese. This stirring is accomplished by a rotary motion, and the use of a brake, which is a piece of wood closely fitting the side of the kettle. This creates an eddy in the current at that point and gives a more uniform distribution of temperature. The process of cooking takes from thirty to forty minutes, and at the end of that time the degree of toughness may be determined by making a roll of curd in the hand, and noticing the break when it is given a quick flip. A short sharp break indicates the desired toughness.Draining and hooping.—In this process, the cheese-makers' skill is displayed. With the hoop prepared, and the curd at the correct stage of toughness, the operator takes a press cloth, wets it in whey, slips it over a flexible iron ring which can be made to fit the shape of the kettle, gives the contents of the kettle a few swift revolutions, then suddenly reverses the motion, with the result that the contents form into a cone, and the ring and bandage are dexterously slipped under this cone, and drawn up to the surface of the whey with a rope or chain and pulley. This part of the process is the most important, as a cheese must have a smooth firm rind, else it will quickly crack. With too large a batch of milk, the curd can be cut into two pieces and hooped separately. With the mass of curd at the top of the whey, the piece of perforated iron plate just the size of the hoop is slipped under the mass, and attached to the pulley by four chains. Then the top of the mass is carefully leveled off, because while still in the whey, it cannot mat badly and so tend to develop a rind crack. Now the mass is raised clear of the whey, and run along a short track to the drain table, where it is put in the press.

Pressing.—The mass of curd is dropped into the hoop, the edges of the cloth carefully folded under, and the cloth laid on top, then the pressure is applied, gradually at first, but increasing until the final pressure is about fifteen to twenty pounds to a pound of cheese.

During the first few hours the cloths must be changed frequently, and the cheese carefully turned over each time, to secure a more uniform rind. After a time the changes are less frequent, and at the end of twenty-four hours the cheese is taken to the salting-room.Salting may be done by either the brine or dry method. To prepare a brine bath, add salt to a tank of water until it will float an egg, and add a pailful or more of salt every few days thereafter to keep up the strength. The cheese is then placed in this bath and left for three to five days, depending on the saltiness desired. As the cheese floats with a little of the rind above the surface, it should be turned a few times to insure uniformity of salting. With dry salting, the salt is rubbed on the cheese by hand or with a stiff brush, and any excess carefully wiped off, leaving only a slight sprinkle on the surface to work into the cheese.

271. Curing Swiss.—From the salting-room, the cheese goes to the first one of two curing-rooms, where the unique process of the development of the characteristic eyes takes place.

During the curing period of either round or block Swiss, constant attention must be paid to the cheese. They must be turned every day at first, and then every second or third day toward the end of the curing period. Also, great care must be taken that no mold starts growing, as it will soon work into the cheese, and spoil its flavor. The best way of preventing mold is by washing the cheese, in either clean or slightly salted water, as often as possible. A stiff brush is mostly used for this.

The development of the "eyes" or holes is the difficult part of the whole process. It is not known exactly what causes the development, but it is attributed to micro-organisms or enzymes. The gas in these eyes has been examined and found to be carbon dioxide and free nitrogen. Sometimes hydrogen is found. This comes from the original fermentation of the milk-sugar and remains to contaminate the normal eye. The nitrogen124 is included from the original air. Propionic acid is formed at the same time as the eyes, and they are said to be the result of a propionic ferment of lactic acid. The interior of the cheese is anaËrobic, due to low permeability and high oxygen-absorbing quality. This propionic bacterium cannot, however, account for all the carbon dioxide produced.

After the eyes have started, their further development depends on temperature and humidity of the air, and on the moisture of the cheese, as regulated by the amount of salt used. The first room has a temperature of 70° F. to start the eyes, which is later lowered in the second curing-room to about 60° to check the development. When any local fermentive action starts, it may be checked by rubbing salt on the affected part. The humidity of the room is very important, because a cheese will quickly dry out in a dry room, due to evaporation from the surface. To prevent this, it is well to spray the floor with water, or to have a steam jet in the room.

If the curd has been cooked too long the cheese may be too dry. Such cheeses may be piled two or more deep in the curing-room. It is held by some cheese-makers that this process causes them to absorb more moisture. Probably this is due to the checking of evaporation.

The development of the "eyes" may be watched by trying the following test: Place the middle finger on the cheese and let the first finger slip from it, striking the cheese smartly; a dull sound indicates solidity, while a ring indicates a hole, and an expert maker can tell the size of the holes by the sound. This requires long practice for the operator to become proficient.

After a cheese has remained in the first room for about two weeks and the holes are well started, it is removed to the second curing-room, which is held at a cooler temperature and slightly drier atmosphere. The cheeses are held in this room from three to ten months, depending on market conditions, and capacity of the curing-rooms. In Switzerland, it is customary to hold cheese to secure a well ripened product, while in America most of the cheeses are shipped comparatively green, hence do not bring so high a price.

272. Block Swiss.—In making block Swiss, the same procedure is followed through the cooking stage. Then the curd is pressed in a square form or in one large piece, each form six inches square on the ends and twenty inches long, and later cut into sections. These are then pressed, salted and cured in the same way as round forms. In this type of cheese there is a much smaller cross-section; therefore the development of holes is much more easily controlled on account of the ease with which the salt can work into the cheese and control undesirable ferments. As it is easy to control, this variety is made in the fall and winter when the ferments are especially hard to keep in check. However, this cheese has the disadvantage of cutting eye-development short by the rapid entrance of salt.

The curing consists of the developing of the flavor and eyes and the changing in body and texture. Just what causes these changes is not known.

273. Shipment.—When ready for shipment, the drum cheeses of the same general diameter are sorted out and packed four to six in a cask. Care must be taken to put boards between them to prevent sticking. These are called scale-boards, and are made of thin sections of wood fiber. The cheeses are crowded into the cask to make a snug fit, and the head carefully fastened.

274. Qualities of Swiss cheese.—The peculiar Swiss cheese flavor may be characterized as a hazel-nut taste. It is a trifle sweet and very tempting. The "eyes" or holes should be about the size of a cherry with a dull shine to the inner lining. The "eyes" usually contain a small amount of a briny tasting liquid. These eyes should be uniformly distributed. The color should be uniform. The cheese should have a neat, clean, attractive appearance, and the rind should not be cracked or broken.

There are several common defects in Swiss cheese. If the milk is not clean-flavored, the cheese will have the same flavor as the milk. The greatest difficulty is to produce the eyes or holes. A cheese which does not have these is called "blind." A product which has many small pin-holes due to gassy fermentations is called a "niszler"; this means a cheese with a thousand eyes. If gas forms in the cheese and causes cracks, it is called "glaesler." If the cheese contains too much moisture, it will be soft and pasty. Such a cheese does not readily form eyes.275. Composition and yield.—A large number of analyses of Swiss cheese have been made but there is wide variation. This is due to the fact that the composition and yield are both dependent on the following factors: composition of the milk, losses during manufacture, amount of moisture in the cheese. The losses in Swiss cheese are much larger than with some of the other hard cheeses, such as Cheddar. This is because more fat is lost in the whey, due to breaking instead of cutting the curd and the subsequent hard stirring. The possibility of reducing these excessive losses has already been indicated.

Swiss cheeses of high grade show about the following range of composition:

The water-content of this type of cheese is low and the protein-content is proportionately high. Both conditions lead to firm textures, long ripening and long keeping periods.

The following score-card is used to judge both block and drum Swiss cheese:

The yield of Swiss cheese varies from 8 to 11 pounds to 100 pounds of milk. The more solids in the milk, the more moisture incorporated in the cheese; the smaller the loss of solids in the manufacturing process, the larger will be the yield from a given amount of milk.

THE ITALIAN GROUP125

A group of varieties, best known in America by Parmesan, are made in Italy with related forms in Greece and European Turkey. These forms are very hard, usually uncolored, with small eyes or holes. They are made in large cheeses which ripen very slowly. Cow's milk is regularly used for Parmesan and Grana in northern Italy; other varieties contain goat or sheep milk or various mixtures. Aside from Parmesan, few of the other forms are known outside the place of origin except as they are exported in a small way to satisfy the demand of emigrants from these regions.

276. Parmesan.—One type of Italian cheese, however, the Parmesan, has become very widely known. In general the consuming trade does not discriminate between Parmesan, Grana and closely related forms. Parmesan is made in large cheeses which require one to three years for proper ripening; in texture it is very hard with small eyes or holes formed by very slow fermentation. Such cheeses are ripened in large storehouses in which hundreds and even thousands are brought together and cared for by experts. The surfaces of these cheeses are kept clean and free from insects by rubbing with linseed oil. So hard are these forms that the cheese-trier is not used in testing, but the texture of the surface is tested by pricking with an awl-like tool and the stage of eye-formation and associated ripening is determined by the sound given out when the cheeses are tapped with a hammer.

When ripe, the cheeses of this group are used in cooking principally. The broken cheese is grated and added to macaroni, spaghetti and other cooked cheese dishes. Parmesan is usually made from partly skimmed-milk; the ratio of fat to protein in analysis runs from 1:2 to 3:4 in contrast to the normal relation of about 4:3 in whole-milk cheese. In water-content much variation is found, but ripe Parmesan is usually about 30 per cent water. Other members of the group are made with different amounts of skimming, some of them from whole milk. The group in general represents the requirements of cheese for the trade of warmer regions (see Mayo and Elling): (1) a low fat-content so incorporated that the cheese does not become greasy or oily in hot weather; (2) a water-content low enough to prevent rapid spoilage during the necessary exposure of handling under warm conditions.

The equipment for Parmesan manufacture has more resemblance to that of the Swiss factory than the English and American cheeses. The milk is curdled in deep copper kettles (Fig. 57), below which there is commonly a provision for direct heating by fire which is sometimes carried on a truck, and therefore can be withdrawn when heating is sufficient. The steam-jacketed kettle has replaced this earlier form to a large measure.

Fig. 57.—Parmesan cheese kettles.