Hints on cheese-making, for the dairyman, the factoryman, and the manufacturer

by T. D. Curtis

CHAPTER XV. HEAT.

One of the most important elements in cheese-making is heat; but we do not believe the importance of its proper regulation is sufficiently understood by our cheese-makers. We are aware that cheese can be made without the use of artificial heat. It is not such an article, however, as would meet with a ready sale, or be likely to increase the consumptive demand for cheese. A good-keeping, mild and nutty-flavored cheese cannot readily be produced, if at all, with a temperature lower than 96°; nor can a rich, buttery article be made with a temperature over 102°. We consider 6° the widest allowable range of heat, and think 98° to 100°, or full blood-heat, the best temperature.

Evenness and steadiness of temperature are two important points. That apparatus is best which heats the milk throughout the vat the most evenly—leaves it the freest from hot places and cold places, at the sides, ends, or on the bottom. A perfect apparatus would raise the temperature of every particle of milk at the same time and at the same rate; and retain this perfectly even heat at the desired point until the cooking is completed.

The difficulty, with most or all heating apparatus, is to raise the heat of the entire mass to the required temperature, without submitting some particles to a greater degree of heat than is necessary, or heating them in advance of the rest, to be stirred in and partially cooled again.

We believe that an even cook or scald is of the utmost importance, and that everything that can be should be done to secure that end. If thoroughly accomplished, with sweet milk to begin with, we have no fears as to the richness, fine flavor and good keeping qualities of the cheese. There is no other thing, in our opinion, which will go so far toward securing these three desirable qualities.

Another thing, as before indicated, we consider of great importance in securing a thorough cooking and proper separation of the whey from the curd. We refer to steadiness of temperature. It seems to us a great mistake, when the temperature is once up, to not keep it there, without rising or lowering. It seems a misapplication of terms to speak of cooking or scalding at a temperature of 98 or 100 degrees; yet, we all know that blood-heat is all that is required for cheese-making. This heat seems necessary. Perhaps it is because nature designed the gastric juice from the rennet to operate at the temperature. It is a well established fact that digestion will not go on when the temperature of the stomach is below that of blood-heat. We presume a much higher temperature is equally detrimental. This may account for the fact that blood-heat is the best for cheese-making, as at that temperature the rennet is most active. Be this as it may, we are satisfied that the process is retarded and the curd deteriorated by allowing the temperature to fall during the time it is in the scald. Instead of cooking, and condensing, as it should, in order to expel the whey, it is only soaking and souring. The moment the acid is sufficiently developed, though the curd be yet soft and raw, the whey is drawn, the curd is further cooled and soaked, and then dipped, drained, salted and put to press. A leaky cheese is the result. If the weather is cool and bad for curing, a sour cheese follows. But whatever the weather may be, we doubt if a leaky cheese ever yet turned out all right in flavor and quality. It can never have that nutty, new-milk flavor which belongs to cheese properly cooked. We presume there are those who will differ with us in opinion, but we should demand the positive evidence of at least four senses before believing we are wrong.

We say, therefore, raise your temperature gradually and evenly, to full blood-heat, and there retain it until your curd is ready to dip. Then we believe it would be an advantage to dip and drain, without cooling more than what cannot be avoided, and salt warm. But of salting, we will speak more at length some other time. We are now discussing the question of heat. Let us give a little every-day illustration. Suppose the housewife were to put her potatoes for dinner in a kettle of water, run the heat up to 212°, and then allow it to cool by radiation until the potatoes are done. What kind of a dish would they make? Or, after she had cooked her potatoes, suppose she should let them stand and soak until they are cool enough to handle without danger of burning or scalding any one. Who would want to eat the watery things? The truth is, 212° is the proper temperature for boiling potatoes, and the sooner and hotter you can get them out of the water, the better. So, in our opinion, blood-heat, or 98° to 100°, is the proper temperature for cooking cheese curd, and that after the curd is done, the sooner and warmer it is dipped, the better for the curd—the sweeter, richer-flavored and better grained (not pasty, but more of the consistency of hard, well-made butter, which shows the batter globules whole) will be the cheese, and its keeping qualities will be correspondingly improved. It may be a little more work to cool the curd in the air, and harder keeping it from packing; but if dipped warm, the whey will the sooner drain off, and the salt can be the sooner thrown on, when it will penetrate quicker, season the mass more evenly, and form a coating to the particles of curd, which will keep them from packing together.

But whether the curd is cooled before dipping or not, we maintain that it is a great advantage to keep the temperature up to blood-heat during the entire process after the heat is once raised. With self-heating apparatus, this can be done by keeping a very little fire going—just enough to supply the loss of heat from radiation. Where the heating is done by running warm water around the milk-vat, a current of the proper temperature can be kept up. If steam is used, perhaps a small jet can be kept pouring into the space around the vat. But in all these cases, the danger is that too high a temperature will have to be kept up at the point of applying the heat, in order to prevent the temperature of the whole mass from falling. This is a decided objection, and necessitates a great deal of stirring, which is only a palliative of and not a remedy for the evil.

Of course we write with reference to the management of heat with milk that is sweet and in proper condition for cheese-making. Where it is "old," or tainted, to begin with, it is necessary to hurry the heat, and every operation connected with the process of making it up. A higher temperature and less time will be found to produce a very similar effect to a lower temperature and more time. But, in all cases, an even, steady heat should be aimed at and maintained to the end.

We never could quite understand the philosophy of cooking less in the spring and fall than in the summer. The idea that it makes the cheese more buttery to dip the curd raw, seems to us very absurd. If there is any time when a curd needs to be thoroughly cooked, it is when the weather is cool and unfavorable for curing. If the whey is not properly expelled by the action of heat, it has got to either dry out or leak out, or both. If there is too much left in the curd to dry out, long before it can leak out, your cheese will be sour, with a puckered face, and sundry ugly cracks. Even when the cheese does not absolutely drip, if the curd is dipped while underdone, it will sour, the face will have a corrugated appearance, and the cheese will "try" crumbly and sour. The color will also be paler than in those that are properly cooked, the general look will be clammy, and no rind will form that will be satisfactory. Even when well-cooked and well-made, if a cheese does not have sufficient warmth, it will sour on the ranges and spoil; and it stands to reason that cheese made from a curd insufficiently cooked must work a great deal worse under unfavorable conditions for curing. Our experience is, that a curd needs more cooking in the spring and fall than will answer in hot, dry weather. If we must have a curd dipped soft at any season of the year, we say let it be at that season when the weather is best for drying and curing. A cheese that would become worthless on the ranges in cold, wet weather, may turn out pretty fair in "dog days." But we do not believe in undercooking at any time. Food, of all kinds, needs as much cooking one season of the year as another. It is quite likely, however, that a degree or two lower heat will answer in cool weather, for the reason that milk keeps better then, and the curd remains longer in the scald before taking on acid. In this case, we have a lower heat for a longer time, which will produce the same result as a higher heat for a shorter time. But in both cases the curd ought to be cooked the same. Whatever degree of heat is decided upon, let it be kept up, steady and uniform throughout the mass, and at all seasons of the year let the curd be cooked done. This is specially important when the conditions for curing are unfavorable. You must do, then, in the vat part of the work which can be done on the ranges when the weather is favorable.