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in executing the work; and hence, perhaps, the various opinions as to an absence of novelty. My process is similar to the old American private dairy system in this : that in both, the whey is drawn sweet, but in the dairies, the curd, when separated from the whey, was that once salted and pressed. But I give an extensive ripening of the curd after it is out of the whey before even applying salt. Here is an important difference. I make the same difference with those who use the Dunlop, Wiltshire, etc. They draw sweet, and apply rennet at as high a temperature as I do, but they also press too soon. The Cheddar process comes nearest my mode, but the two separated at an important point. The Cheddar men (about one-half of them) draw their whey sweet, as well as I. They make it a point to ripen the curd after it is out of the whey, and so du I. They drain their curds and pack them in the make-vats, turn them occasionally to keep them warm alike, and let the whey run off; and at first I did the same. But the polar stars toward which we travel lie in opposite sides of the heavens. The Cheddar men, according to Prof. Willard, work on an acid basis; I on a sweet one. They ripen their curds to a certain stage of acidity ; I bring mine to a certain stage in respect to cheesing. If the milk is suspected of being too sweet for them, they put sour whey into it with the rennet to hasten the souring, and they work all the way through with a view to encouraging and cultivating acid at about a certain time, and their manipulations are well shaped to that end. I, on the other hand, avoid the use of acid in any and every way, and work to put it off as long as I can, and, if possible, to steer clear of it entirely. Milk is never too sweet for my process, though but one minute from the COW.
These two conditions of cheesing and souring have no necessary connection with each other. The former depends on the action of rennet and oxydation ; the latter on fermentation. They may or may not advance alike. Either one is liable to be in advance or behind the other by a variation in the condition of the milk. If it has a certain condition, they may advance alike, that is, when the souring has reached a certain condition assumed to be the proper one for salting and pressing, the cheesing will also have reached the stage for salting and pressing, and a favorable result will be had. But if the milk is too sweet or too stale, the acid will be either behind or in advance, and in either case, a balk will result.
By the Cheddar process (and the same is true with the common process), cheese can only be made uniform by having the milk all the time in a certain and uniform condition. Otherwise the souring will occur at the wrong stage; and this is the reason that Cheddar cheese varies so much, and so little of it is fine; and this same difficulty lies in the way of the common acid process, and all others also which do not have regard to the advance of cheesing in treating the curd, because it is extremely difficult to get milk which will run all the time alike.
In the new departure the case is materially changed. We can bring the curds to a uniform condition, though the milk from which they are derived dissers quite widely, and thus secure a closely uniform result in the mature cheese. There is no other process that I know of which can do this. The reason of this wide difference is that the old practices are empirical, while I work in accordance with natural laws and have a sound reason for every step in the progress.
At the time I took a stand against acid the manufacturers were all leaning on it as a sine qua non, the trade were fairly sour with it, and it was dripping from the pen of every dairy writer in the country. With a full knowledge of the certainty that all these parties would " sour on me," and in view of the strong hold which our sour goods bad obtained in the British market, and the large and profitable trade going on in them, it seemed a bold undertaking to stand alone on a platform of one's own building with a view of holding out against the opposition which would certainly be encountered. It required some courage, but being " sure I was right I when ahead.” The suggestions offered at the Convention above named, and at others later in the winter, were approved by many, and several attempts were made the following summer to carry them out, in which the failures were more numerous than the successes. There was nothing in these failures, however, to militate against the principles adopted. They were occasioned by some defect in the mode of working. Enough were successful to give encouragement for further effort. The first cheese maker to whom an explanation of the process was given took it from a verbal statement and made a complete success of it.
Though in a bad location for milk (Farmington, Michigan), where, by the acid system, failure had been the rule for three years in succession, upon the adoption of the new plan the failures ceased, and not another one has occurred since, the factory having now run two full seasons after discarding the acid. In the season of 1878, I spent some six weeks in Pennsylvania, working one day in each factory, and carrying out the non-acid principle as nearly as the circumstances would permit. Though not in every instance successful, the result went stongly to sustain the correctness of the position at first started with. The obstacles in the way were sometimes slight and sometimes fatal. Two serious diffiulties were pretty sure to be encountered in every factory. The first was in respect to the rennet. The universal practice was to soak rennets in sour whey,
large quantities being used. To curdle milk for a sweet curd cheese with a liberal use of sour whey was, in effect, throwing a wet sheet over the result. But there was generally nothing else in the factory that could be substituted, and it had to be used. The other difficulty was that the workmen had so long depended on acid as an absolute necessity that they could not give it up. The hot iron test had been the only guide for dipping, and it seemed almost impossible to lay it aside. The operator felt so much at sea without it that the iron would be thrust in the fire and the curd tested till it would "just start.” By the time the curd could be got out of the way it would be distinctly sour, and the result would be one more step further from a sweet process. But generally, doing away with even a part of the acid made an improvement in the cheese. As a whole, the result encouraged further effort to give the new system a foothold in other localities.
Last summer, a few months spent in Canadas proved more successful. Better rennet was furnished, generally rennet extract or gocd rennets soaked in weak brine. For the most of the time, three days were spent in each factory, and this gave the makers, who were present, an experience that seldom led to make them so familiar with the process that that they could execute it successfully without further aid. A few failed and fell back upon their sour whey and hot iron. Those who have mastered it are highly pleased with it, and would not, on any account return to their former mode.
The better success in Canada was due also partly to better curing rooms and partly to improvements adopted in carrying out the system. Starting of on a new track without any experience, it would have been a marvel if every step had proved to be the best that could be taken. The plan adopted at first was to draw the whey sweet and then pack the curd against the sides of the vat, after the manner of the Cheddar practice; and this worked very well, but it had its objections.
Though the plan of handling the curds first started out with proved superior to any other in use, it was not in all respects satisfactory. By packing the curd in the vat it had the advantage of retaining heat well, but if kept as warm as it should be, the gas would form inside of it faster than it could escape, and the curd would become full of holes, like dough when rising. The holes did no hurt of themselves, and the gas
that was in them was harmless, but they made a receptacle for catching and holding the whey and water which were always separating within the solid curd. The whey thus enclosed being in a warm corner would quickly sour, and, according to the amount retained, would harm the curd by its contact just the same as would the sour whey in which curd might be lying. Upon grinding, a part of it would escape, but most of it would remain in till pressed out. While enclosed in the gas holes the retained whey was clear, and would drain out clear if left to itself, but when, by heavy pressure, it was forced out through the walls of curd, it would carry cream along with it and become "white whey," diminishing both the weight and richness of the cheese. Though the curd, when packed, as in thc Cheddar process, would, at the same temperature, ripen faster than when enveloped in whey, it would have ripened faster still if more exposed to the air. The handling of the curd was, therefore, changed, and instead of packing, it was kept fine as well as warm, improving the cheese while it hurried the work. It obviated entirely the occurrence of white whey, and gave a more complete oxydation of the curd, and kept it sweet for a much longer time.
In 1878, in connection with Dr. F. E. Engelhardt, of Syracuse, I followed up the investigation of cheese, as affected by acid, in a series of experiments by digesting it with gastric agents analagous to human gastric juice, making near one hundred experiments, embracing every variety, foreign and domestic, we could obtain, the results of which were presented to the Association last year. By these experiments it was clearly established that the cheese made with the least acid digested soonest and most completely. In several samples, like the Roquefort, English dairy, and others made entirely sweet, not only was the digestion of the cheesy matter perfect, but the fats were also acted on and entirely disappeared in the clear chyme. The samples which had been most freely treated with acid digested very slowly and imperfectly; sometimes not more than one-tenth of the caseine being dissolved, and the fats not acted on at all. The contrast was most remarkable, and was enough to set at rest forever the deleterious influence of acid in cheese making. But from the first other evidences have been multiplying, and still continue to accumulate. Recently a little book on milk, by Dr. Flieschmann, was handed me by Dr. Caldwell, in which there is an interesting account of some experiments upon the solubility of caseine made by Hammerstien, of Germany. It appears from them that the solubility of caseine depends largely, if not wholly, upon the presence of phosphate of lime, a substance which constitutes from one-half to threequarters of the ash of milk. He found that when it was present in curd in the largest proportion it was completely soluble, and that when it was removed the caseine became insoluble. He found, also, that when the milk was coagulated with rennet the phosphate was all retained in the curd, but when coagulated with acids a large part of it was separated
and passed off with the whey, leaving the surd insoluble. Analyses of of the whey showed about three-quarters of the phosphates in its ash.
These developments explain scientifically the cause of the indigestibility of our acid factory cheese, the facts concerning which I have so often noticed and published. They explain what must take place in a common practice I have long and earnestly objected to as injurious to the curing and digestibility of cheese. I allude to the use of sour whey in the preparation of rennet. They show that whoever soaks his rennets in sour whey, or puts it in his milk to hasten a hot-iron test of acidity at a certain time, does an irreparable injury to the digestibility of his cheese, and becomes an active promoter of the steady decline in its home consumption which has been going on since the introduction of the factory system. People like ours, who have the liberty of choice in their food, will not select indigestible cheese. Those who have no choice will take what they can get.
The experiments of Hammerstien do not go quite far enough to cover all the trouble from our acid cheese making. They leave out the effecte of letting good curd made with rennet lie in the whey till the latter ferments and becomes sour. Seeing this omission, I have just begun making some tests in Dr. Caldwell's laboratory, to determine what effect the acid thus developed has upon the separation of the phosphates from the curd. They are not yet completed, but one of them is so far along as to show that curd made with pure rennet and left in the whey till it became sour, as in the common practice of making in the factories, had 14 per cent. less ash than curd taken out of the same batch while it was sweet. As nearly all the ash of curds is phosphates, the 14 per cent. can be counted as so much affecting solubility. More experiments are necessary to a full determination of the loss in phosphates by souring in the whey; but this one being in accord with those of the German chemist and with the practical effect such souring has upon cheese, is strikingly corroborative of the position I have maintained in regard to letting curd lie in whey till it sours.
In the fall of 1875 I asked Dr. Caldwell to make some experiments to determine, if possible, the changes which occur within a cheese while curing. He consented to do so if I would furnish him cheese of suitable size for his apparatus, and would call at his laboratory as often as I could to keep trace of the work and to indicate just what it was desired to have done, and to offer any suggestions that might occur; all of which I was very glad to do. I applied to William A. Johnson, of Erie county, New York, and he kindly made three cheeses of the desired size and form, and sent them fresh from the hoop to the University, generously donating