Thursday, December 26, 2013

The Process of Making Swiss Cheese

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. 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.

Thursday, December 12, 2013

Swiss Cheese's Clean, Unacidic, Unfat 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.