CHAPTER XIII. SETTING.
The temperature of 82° to 86° is generally considered the best for setting—the former in hot and the latter in cold weather. This gives an average of 84° for mild weather. Perhaps this point is as good as any for setting. But it is worth bearing in mind that the milk will coagulate sooner, after adding the rennet, at a high than at a low temperature. The same milk will set quicker at 86° than at 82°, and at the points in the vat where the heat is greatest, or the milk cools least by radiation, the curd will become tough and difficult to cut, while other parts of the mass will remain tender and cut easily. This not only demonstrates the greater activity of the rennet at a higher heat, but the importance of an even heat throughout, and of keeping it from falling. Some throw a cloth over the vat, after the milk begins to thicken and agitation is no longer necessary to keep the cream from rising. This is a good practice, we believe, as it retards the reduction of temperature by radiation, and keeps the heat more equalized. This will secure a more uniform action of the rennet, and render the cutting less difficult and less liable to cause waste.
When the rennet is once added and thoroughly incorporated with the milk, we believe it would be better if the mass could have perfect rest until the curd is ready to cut. We think the curd is more likely to be spongy in consequence of the continued or frequent agitation kept up to prevent the cream from rising. All know that a stir too much after the milk begins to look thick, and roll heavily, prevents the formation of a solid curd. It refuses to unite in one uniform mass, and remains in small, separate particles. But, when the milk is all right, observation will show that such a curd makes fine cheese, though there is great waste from the fine particles floating off with the whey. And why will it make fine cheese? Because it is in small particles, gets thoroughly and evenly cooked, and the butter is equally distributed through it.
But the difficulty of preventing the cream from rising and forming a cream-curd, that will float on the whey, if it does not waste, needs to be overcome before we can allow the milk perfect rest after incorporating the rennet. We are not aware of any method for accomplishing this. Agitation of the surface, at least, seems necessary to retain the cream; but if the surface only is agitated, manifestly the cream will escape from the bottom of the mass and impoverish it while enriching the top. A thorough stirring of the whole mass, therefore, will keep the cream more equally distributed, and it will also secure a greater uniformity of temperature. The cheese must be of evener texture than if made of curd of different degrees of richness mixed together.
It is a question for debate as to whether the cream which rises on milk is thoroughly incorporated with it by stirring. That butter is wasted in making cheese, is a fact that cannot be denied. Some think that nearly all the cream that rises on the vat during the night is floated off in the whey. We cannot indorse this conclusion, although it is asserted that where agitators are used, and the cream is thus prevented from rising, there is a great saving of the butter. But one fact is worth a thousand fictions in the practical affairs of life, whatever it be in romance. Cream will mix with the milk by stirring, and go to enrich the cheese, as is proved in the manufacture of the English Stilton cheese. In the manufacture of this, the cream of the night's milk is taken off and added to the morning's milk, which is worked up separately. The cheese is greatly enriched thereby. How much the waste of butter is increased, we are unable to say. We know from our own experience, that skimming the night's milk, instead of stirring in the cream, makes a marked difference in the yield and quality of the make.
The first thing in setting, when a vat of milk is raised to the proper temperature, is to add the coloring. This is a strong alkaline preparation, and must have a tendency to retard the development of the lactic acid, if it does not combine with it in forming a neutral salt. If no effect is perceptible, beyond the color it imparts, it is simply because the quantity is so small. Probably the effect of the alkali in the annotto is more than counteracted by the acid in the rennet.
Nothing as good as clear whey has been found for soaking rennets. Some think the acid an advantage in the working of the milk, and others go so far as to add, in cold weather, a quantity of sharp whey to the milk along with that in the prepared rennet. This, of course, hastens the development of acid throughout the mass. But we cannot say that we approve of doing anything to change the milk, and thus sour the curd before cooking. We prefer to have the milk as sweet as possible when set, and to keep the curd sweet until it is cooked. Then we would develop the acid in the whey. For this reason, if sour whey is to be added, we should add it after the curd is cooked, for the purpose of hastening the development of the lactic acid in the whey. This seems to us to be the most rational course, from what our experience has taught us. If fair experiment should demonstrate that we are in error as to when and where the development of the acid should take place, we shall be willing to yield the point.
The amount of prepared rennet that it is necessary to add to the milk, depends upon its strength, which can be determined only by experiment. Sufficient should be used to coagulate the milk in ten or fifteen minutes, and render it fit to cut in thirty or forty minutes. If the milk is "old," the same quantity of rennet will cause it to work sooner, as it should. Some would add less rennet. We would not. The milk needs to work faster, and the acid, although it coagulates the milk, will not supply the place of the rennet. The rennet ought to be strong enough to require not more than a quart to a thousand pounds of milk.