_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 subst.i.tuted 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 ma.s.s of curd at the top of the whey, the piece of perforated iron plate just the size of the hoop is slipped under the ma.s.s, and attached to the pulley by four chains. Then the top of the ma.s.s is carefully leveled off, because while still in the whey, it cannot mat badly and so tend to develop a rind crack. Now the ma.s.s 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 ma.s.s 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 nitrogen[124] 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 anaerobic, 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 ga.s.sy 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 a.n.a.lyses 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:

Water 30-34 per cent Fat 30-34 per cent Protein 26-30 per cent Ash 3-5 per cent Salt (NaCl) 1-1.4 per cent

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:

Flavor 35 Appearance on trier holes 30 Texture 20 Salt 10 Style 5 ---- 100

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 GROUP[125]

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 p.r.i.c.king with an awl-like tool and the stage of eye-formation and a.s.sociated 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 princ.i.p.ally.

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 a.n.a.lysis 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.

[Ill.u.s.tration: FIG. 57.--Parmesan cheese kettles.]

The general character of the manufacturing process is indicated in the following abstract of one of the methods. Many variations are to be found. The milk for Parmesan is allowed to stand overnight. Some acidity is, therefore, developed in contrast to the absolutely fresh condition of the milk used in Swiss and the acidification developed during the making of Cheddar (Fascetti). It is then skimmed, heated to 72 to 75 F. Rennet is added in amount sufficient to produce firm curd in one hour or slightly less. When the curd is firm, a wood fire is made under the kettle and the curd is broken with a special implement into small particles. After breaking, four grains of powdered sulfur to twenty-two gallons of milk are added. The curd is stirred with a rake. By the time the temperature rises to 77 F., the curd should be in very small pieces. Stirring and heating continue until the temperature reaches 131 F. At this temperature, it stands fifteen minutes, after which it is removed from the fire (or the fire is drawn). Nine-tenths of the whey is then drawn. The cheese-maker then collects the curd into a compact lump under which he slips a cheese cloth. With the aid of an a.s.sistant he removes the ma.s.s to a perforated vessel for draining. After this the curd goes into large wooden hoops, lined with cloth, which stand upon a slanting draining table until evening. No pressure is used. Before night they are taken to the cellar. The cloths are removed next day.

After standing four days, they are salted by covering the upper surface with coa.r.s.e salt. This is repeated with daily turning for twenty days, then salted on alternate days for another period of twenty days. At the end of the forty days' salting, the cheese is removed from the hoop, sc.r.a.ped, sprinkled with whey and the rind rubbed smooth. A dressing of linseed oil either with or without bone black is applied.

[Ill.u.s.tration: FIG. 58.--A typical cheese-market in France.]

The cheeses are kept in special ripening rooms, and rubbed frequently with linseed oil to keep the surfaces free from molds and vermin.

Careful grading as to quality of product and consequent response to ripening conditions produce cheeses of many degrees of excellence.

Those in which a ripening of three to four years is possible are most highly esteemed.

+277. Regianito.+--A cheese of the Italian group is now made in Argentina and imported to the United States under the name Regianito.

CHAPTER XVI

_MISCELLANEOUS VARIETIES AND BY-PRODUCTS_

As already discussed in Chapter VI, there are a large number of varieties of cheese. Very many are entirely unknown in America. A considerable number of forms are occasionally imported and may be found by visiting the markets and delicatessen stores in the foreign districts of our large cities. Certain forms not widely known are made in America in a few factories or are imported in sufficient quant.i.ty to call for brief discussion. Some of these are brought together here.

The importance of the by-products of cheese-making has not been sufficiently recognized, for manufacture on a large scale is only beginning to be appreciated in America. Certain cheese names, such as Mysost, are applied to whey products. In addition, milk-sugar is extensively made and whey-b.u.t.ter has been carefully studied and found to be practicable under some conditions.

+278. Caciocavallo+ originated in Italy, but is now made in certain factories of New York and Ohio. Some factories in Lombardy[126] use whole milk, others use half-skimmed milk. The latter practice is probably the more common. In making this cheese, the milk is coagulated with rennet, cut and firmed in the whey, allowed to settle and the whey drawn. The curd is then piled on the draining table and allowed to mat or fuse into fairly solid ma.s.ses. After several hours of draining and matting, the curd is cut into strips and placed in a vat of hot water.

In the hot water, the blocks of solid curd melt into taffy-like ma.s.ses which are worked and molded by hand into more or less standard shapes.

Indian club or ten-pin forms are most commonly produced. When the proper shape has been gained, each ma.s.s is thrown into cold water which solidifies it in that form. Cheese ma.s.ses heat and cool slowly; several hours of cooling are required to insure a firm cheese. The newly made cheeses are salted in a brine bath, then hung by a string to ripen.

Sometimes these cheeses are eaten fresh, again they are ripened several months. They vary in size from one to six pounds. Cornalba gives the composition of Italian Caciocavallo made from whole milk as water 32 to 34 per cent, fat 34 to 36 per cent, protein 28.5 to 29.5 per cent, salt 1.7 to 1.8 per cent; when made from half skimmed-milk, water 28 per cent, fat 27 to 28 per cent, protein 35 to 40 per cent, salt 2.2 per cent. Other a.n.a.lyses vary widely from these figures on account of the differing fat-content of the milk. No standardized practice has been established in America.

_Provolono_ resembles Caciocavallo in method of manufacture and composition, the main difference being in the shape of the cheese. It is more or less round and is held by a coa.r.s.e net made of small rope. The cheeses are treated while curing the same as Caciocavallo.

+279. Sap sago.+--This hard green cheese imported from Switzerland is made in cakes, tapering from perhaps two inches in diameter to a rounded top with a height of about two inches. These are made from skimmed-milk curd, partially ripened then mixed with powdered leaves of _Melilotus coeruleus_, a clover-like plant. The mixture is then pressed into the market form and dried until very hard. It is handled without special care since the water-content is so low that fermentations are exceedingly slow. This low-priced cheese may be used in cooking.

+280. Alb.u.min cheese.+[127]--In the rennet cheeses, the alb.u.min, which const.i.tutes about 0.7 per cent of the milk, pa.s.ses off in the whey. This alb.u.min is not curdled by rennet. It is, however, coagulated by heating.