( Originally Published 1918 )
"FROM milk," continued Uncle Paul, "we make butter and cheese. I have just explained to you in a few words how the ingredients composing them—that is, cream and casein—are obtained in their separate forms ; but further details are now called for, and I will give them to you, beginning with butter.
"The material necessary for making butter is cream, a fatty substance disseminated through the milk in excessively fine and almost invisible particles. When milk is left undisturbed in a cool place and exposed to the air, these particles of fat rise to the surface little by little and collect there in a layer of cream. An example taken from things familiar to you will explain the cause of this spontaneous separation.
"Oil, you know, cannot in any way be made to dissolve in water. If a mixture of the two liquids is well shaken, the oil divides into an infinity of tiny globules uniformly distributed, and the whole takes on a whitish tint that looks something like milk. But this condition is only temporary. If you stop heating or shaking the mixture, the oil, the lighter part, comes to the surface, globule by globule, and soon the two liquids are completely separated, the oil on top, the water at the bottom. If a little gum were added to the water to make it sticky, the separation of the oil would be less easily effected and the mixture would retain its milky appearance for a longer time; nevertheless the two liquids would always end by separating.
"The fatty matter composing butter behaves in the same way as the oil of our experiment. It is not dissolved by the milk; it is simply divided into very minute particles that are held in place by a liquid thickened with casein, just as water thickened with gum holds for a long time the tiny drops of oil. Left undisturbed long enough, these oily particles free themselves and rise to the surface."
"Cream rises to the top of milk," observed Jules, "just as oil that has been shaken up with water rises to the surface; only the separation is slower on ac-count of the casein that thickens the liquid."
"That is the secret of this curious separation. Milk is placed in large earthen nappies, smaller at the bottom than at the top, and thus a large surface is exposed to the cooling action of the air, which hastens the separation of the cream. The full nappy is put in a cool and very quiet place. In summer half a day is long enough for the rising of the cream; in winter it takes at least twenty-four hours. When the separation is finished, the cream is removed with a skimmer or a large almost flat spoon.
`Cream is yellowish white, oily to the touch on account of its greasy matter, and sweet and very pleasant to the taste, having the flavor of both fresh butter and cheese. It is most delicious eating."
"We know that," Emile assented, "from those capital sandwiches Mother Ambroisine makes for us with cream on feast days."
"That delicacy," remarked his uncle, "cannot be allowed every day, for the cream is needed for butter for the family."
"Once I helped Mother Ambroisine work the little butter machine, a kind of small cask called a churn. Why do we have to thump so long to get the butter?"
"That is what I am going to explain to you. In cream the particles of butter are simply grouped side by side, without forming a united body. Be-sides, a layer of moisture, coming from the whey, isolates them and prevents their uniting. To combine all these particles into a compact mass of butter, it is necessary to squeeze out the milk and knead them together. This is accomplished by prolonged beating.
"The implement used is called a churn. The simplest consists of a kind of small cask larger at the bottom than at the top. The cover is pierced with an opening through which runs a rod carrying a perforated wooden disc on the end inside the churn. After the cream has been poured into the churn, the operator takes the rod in both hands and vigorously raises it and plunges it down in alternate strokes, thus causing the terminal disc to rise and fall in the creamy mass. By this prolonged beating the fatty particles unite and become butter. Sometimes the churn is made of a small cask in which turns by means of a crank an axle bearing perforated wings or blades which beat the cream in their rotation.
"Some precautions must be taken to carry this delicate operation through successfully. During the heat of summer churning should be done only in the morning and in a cool place. It is even well to set the churn in a tub of cold water. If this is neglected the butter may turn sour in the process of churning. In winter, on the contrary, the churn should be kept a little warm by wrapping it in warmed cloths and working it near the fire. Cold hardens the fatty particles and prevents their uniting. If nothing is done to raise the temperature enough to soften them they will be slow in turning to butter and the operation will be long.
"As soon as all the fatty particles are well stuck together the butter is made. It is taken out of the churn and put into cold water, in which it is kneaded over and over again with a large wooden spoon to press out the whey with which it is impregnated.
"If the butter is to be eaten soon, it suffices to keep it in water that is changed every day for the sake of freshness and to prevent the butter's souring. But if it is to be kept for a long time, more thorough-going means of preservation are necessary. The most simple method consists in kneading it with kitchen salt, well dried in the oven and reduced to fine powder. After salting, the butter is put in earthen jars and the surface covered with a layer of salt.
"Another way to keep butter is to melt it. I must tell you, to begin with, that butter, however care-fully prepared it may be, always contains a certain quantity of whey and casein. These are the sub-stances that, changing later by contact with the air, make butter sour and finally rancid. If the fatty matter were all by itself, if it could be completely rid of the casein and whey that go with it, we could keep it much longer. This result is attained by melting.
"The butter is placed in a kettle over a bright fire that is even and moderate. Melting soon begins. The moisture of the whey is evaporated, this process being hastened by stirring the melted mass. A part of the casein rises to the surface and forms a scum which is removed ; another part collects at the bottom of the kettle. When the melted butter looks like oil and when a drop of it thrown on the coals takes fire without crackling, thus proving that it is quite free from moisture, the operation is finished. The kettle is taken off the fire, the liquid is left standing a few minutes to give the casein time to settle at the bottom, and finally the butter is poured by spoonfuls into earthen jars carefully dried in the oven. These jars should be of small capacity and narrow opening, so as to prevent as much as possible the access of air, the cause of change in all our food substances. It is advisable to put on top of the butter, as soon as it hardens, a layer of salt, as is done with salted butter. Finally the jars are closed with parchment, which is tied on with string."