Egerton Ryerson - 1870
Milk - It's Properties, Care and Uses
cent.; and the whey, or watery matter, from eighty to ninety per cent.
The proportions of these several substances vary according to the kind of animal, the food used, and other circumstances. Milk will generally yield from ten to fifteen per cent of its own volume of
cream - the average being about twelve-and-a-half per cent, or one quart of cream for every eight quarts of milk on an average. But the milk of some cows fed on rich food far exceeds this - sometimes furnishing twenty percent of cream, and in rare instances, twenty-five or even twenty-six percent. The quantity of cream obtained is, however, much more uniform than the quantity of butter from cream.
Milk weighs about four per cent more than water; but rich milk is lighter than poor. Cold condenses milk, while heat liquifies it.
The elements of which milk is composed being different in character and specific gravity, undergo
rapid changes when at rest. The oily or butter particles being lighter than the rest, soon begin to rise to the surface in the form of a yellowish, semiliquid cream, while the greater specific gravity of
the whey or watery part, carries it down. The Buttery Particles in rising to the surface, bring up with them many cheesy particles, which mechanically adhere to their external surfaces, thus giving the cream more or less of a white colour instead of pure yellow. Some watery particles also adhere to the buttery particles of the cream, and thus make it thinner than it would otherwise be. If the buttery particles rose up free from the adhesion of the cheese and watery particles, they would appear in the form of pure butter, and thus the process of churning would be unnecessary. But Divine Wisdom has seen fit to require man's agency to prepare nearly all the bestowments of Providence for man's use.
From great heat and sudden changes in the atmosphere (often indicated by thunder), the collection, or coagulation of the cheesy particles sometimes takes place so rapidly, that there is not time for the butter particles to rise to the surface, and they remain mixed with the curd in what is called thick milk. When, on exposure to a warm atmospbere, milk becomes rapidly sour, its sugar of milk becomes what is called lactic acid. It is this sugar and the chemical changes to which it gives rise, that render milk susceptible of undergoing all degrees of fermentation, and of being made into a palatable but intoxicating liquor, which, on distillation, produces pure alcohol.
The temperature of milk as it comes from tbe cow is about blood heat, or ninety-eight degrees of Fahrenheit; and it should be allowed to cool as little as possible before coming to rest in the pan.
The depth of milk in the pans should be shallow, not more than two or three inches. A moderate warmth and shallow depth promote the rising of cream. The temperature of the dairy room or milk cellar should not vary much from fifty-eight degrees - two degrees colder the temperate heat.
The largest butter particles, or globules, are comparatively the lightest and therefore begin to rise first after the milk comes to rest in the pan, and form the first layer of cream, which is the best, as it is less filled with cheesy particles. The next largest butter particles rise a little more slowly, are more entangled with other substances, and bring more of them to the surface. The smallest butter particles rise the most slowly of all, are loaded with caseous or cheesy matter, and produce inferior cream and butter. The most delicate cream and the sweetest and most fragrant butter, are therefore obtained by skimming only a few hours after the milk is set; but from eighteen to twenty-four hours after the milk is set, is the usual time for skimming the cream.
As milk is extremely sensitive to external jnfluences, the utmost cleanliness is necessary to preserve it for any length of time. The pails, strainers and pans, the milk room, and all the surroundings,
should, therefore, be kept neat and clean to an extent which only the best dairy women can
fully appreciate.
On large dairy farms, a building is usually erected as a dairy-house, which should be distant from low damp places, from which disagreeable exhalations arise, and which should be well ventilated and kept clean and sweet by the free use of pure water. But in smaller dairies, economy dictates the use of a room in the house. This room should, if possible, be one on the North side, and be used exclusivel.y for this one purpose. Most cellars are not suitable for setting milk; but where an airy room can be partitioned off from the rest of the cellar, and be thoroughly ventillated by windows, a grealter uniformity of temperature sh'all be secured there than on the floor above. Such a room may be used to advantage but its floors should be dry and porous, not of cement, but of gravel or loam.
Carbonic-acid - a heavy and noxious gas is apt to infect the atmosphere near the bottom of the cellar, and a porous floor acts as an absorbent. It is evident the c:ream will not rise so quickly or so well when the milk pans are set on the cellar bottom. The air is less pure, and the cream is liable to become acrid or bitter. When the object is to obtain the most cream in the shortest time, the milk should stand on shelves from three to five or six feet from the floor, where a free circulation of air can be had from the widows.
