This has been written on so much that the subject has become hackneyed. The acid seems to have eaten into the souls of some and turned them sour; but notwithstanding, the so-called "sweet curd" idea has made steady progress. Much of the opposition has come from buyers for export, who do not appear to be able to distinguish between a firm cheese and a hard cheese, and who ignore quality if they get a cheese hard enough to ship, without danger of breaking, by the time it is ten days old. This has been demonstrated by the fact that cheese condemned when green as too soft has been pronounced by the same buyers fine and all right, even endorsed with enthusiasm, when it was two or three months old, which is about as young as a first-class cheese should be shipped.

ANALYSIS OF MILK.

Of course, there would be no acid in milk if there were no sugar in it. The proportion of sugar is shown by the following analysis of an average sample of good milk made by Dr. Voelcker, the late chemist of the Royal Agricultural Society of Great Britain:

It will be seen by this that the per cent. of sugar is at least 4.50, if we deduct the extractive matter, the proportion of which is not given. Numerous German analyses show it to range from 3.50 to 5.75 per cent. Henry and Chevalier put the average at 4.77, and Prof. L.B. Arnold says milk from cows in perfect health should contain, during the month of August, 4.30 to 5.50 per cent. We will call it 4.50 per cent. There is 87.30 per cent of water.

WHAT THE CHEESE MAKER DOES.

In separating the solids from the liquids, by the action of rennet, at the proper temperature, we expel, say 83.30 parts of the water, leaving 4 parts. We get rid of, say 4.20 parts of the sugar, which is held in perfect solution in the water. We lose, say .50 of one part of butter, .31 of one part of the caseine or albuminoids, and .13 of one part of ash. This leaves—

We thus have 11.20 per cent. of the 100 parts out of which to get our cured cheese. A fair average is 10 lbs. of cheese for 100 pounds of milk. Some of the water evaporates in curing, say 1 part, leaving 3 parts. Our 10.20 parts of cheese is then composed of the following:

This is a little in excess of the general yield. The waste is usually in the greater amount of ash, sometimes nearly the whole of it, when the acid develops before the whey is expelled. In that case, the lactic acid dissolves the phosphates and they run out with the whey. This is so much loss of ingredients absolutely essential to digestion and assimilation.

WHAT OUGHT TO BE.

So far from this, there ought to be less loss of ingredients than we have supposed in our illustrative figures. But more of the butter is cut and runs off with the whey when the acid is developed before drawing the whey. The aim of the "sweet curd" system is to avoid this waste as much as possible, especially that of the butter and ash. To effect this, the whey is drawn sweet and the acid allowed to develop after the curd is cooked and the whey expelled. There need be no more water left in the curd, but more butter and ash, both of which tend to make the cheese softer. But with proper curing rooms, there is no trouble in making the cheese firm enough for all practical purposes, including shipping. It is better to use less rennet and not have coagulation begin under 25 minutes, cutting the curd about 15 or 20 minutes later, and to take more time for curing, at a lower temperature. We then have a firmer, more buttery, and better flavored cheese, which is a desideratum. But, with high and changing temperature in the curing room, no certain or satisfactory results can be counted on.

THEORY AND PRACTICE.

In theory, we ought to prevent the waste of butter and caseous matter altogether; but in practice, there is always a little loss of butter, and there are certain albuminous ingredients, called by the Germans ziega, which rennet will not coagulate. There is, of course, no means of saving this. The sugar we cannot and do not want to save in the cheese. If retained, it would be injurious and probably spoil the cheese, as the lactic acid in the small amount of sugar retained in the water is all that we can well manage. But all matter coagulable by rennet, all the butter, and all the ash, we ought to retain; and we cannot really call ourselves scientific cheese makers until we can do this. When accomplished, a greater weight of cheese will be the result.

There is no avoiding the acid resulting from the small amount of sugar retained in the curd; but, having expelled sufficient whey, if we keep the curd warm enough, and hold it in the vat or the sink long enough, the lactic acid will come on and we shall get rid of the bad results of putting a curd to press sweet. This acidity is absolutely necessary with the generality of curing rooms. But with low and steady temperature in the curing room, we can do about as we please.