Refrigeration.

In order to test whether a special system of refrigerating butter was necessary during its transport from Denmark to England an important series of experiments was conducted by Professor Fjord, of Copenhagen, during the years 1885-86, and the results are perhaps the most important of any which have hitherto been furnished in connection with this question. That a high temperature during transport is detrimental to the quality of butter is undeniable, but professor Fjord found that there was not a consensus of opinion as to whether the quality and state of preservation of butter is better at a lower temperature than is presented by a good cellar in summer, by an apartment in a vessel which is below the level of the sea, or in Railway-wagons during the night. On the other hand, it was the opinion, as it is still, that butter preserved for some time by refrigeration rapidly spoils when placed in the hands of the merchant or the consumer under ordinary conditions. The Danes in particular suffered severe losses by refrigerating butter for the English market, but it undoubtedly often happened that butter which had been refrigerated, and which spoiled more rapidly than other butter which had not, was of an inferior quality at the outset. As refrigeration arrests decomposition in butter, it is evident that it is more difficult to judge when refrigerated, hence it is of importance to know, relatively speaking, how a good and an inferior butter keep after removing from the cold-chamber. Mr. Fjord was assisted in Copenhagen by Messrs. Busch, Routzou, and Plum, all experts, who page 22 judged the butter from day to day during the experiment. The English houses of Messrs. Faber and Co., of Newcastle, and Messrs Sorenson Brothers, of London (with the latter I am well acquainted) placed their warehouses at Mr. Fjord's service, also inviting three merchants in each town to test the butters during the experiment The principal portion of the work was executed by Mr. Storch, the director, and Mr. Lund, the assistant, in the laboratory of the Institut Agronomique, in Copenhagen—an institution of the greatest value to agriculture, and over which Mr. Storch himself very kindly showed me a few years ago. The butter was furnished by three firms living in Zeeland, Funen, and Falster, and by three factories in Falster and Jutland. The butter itself consisted of ninety-four barrels, each containing about 30lb. The method of manufacture was in no case altered, but the articles represented the exact type of ordinary produce. Each sample was divided into two lots, one being sent in the ordinary way of business, while the other was refrigerated or transported into the cold-room. There were four series of experiments in the six dairies. The first series was in 1885, and the second third, and fourth in 1886. In Denmark the barrels were always sent by express and by night-trains, while the butter sent from Newcastle to London left at three in the afternoon, and arrived at five the next morning. The butter which arrived at the laboratory at Copenhagen was immediately placed either in a cellar about 4ft. below the surface of the soil, or in a cold-room. The boats by which the butter was sent left Copenhagen on Thursday evening, and arrived at Newcastle on Sunday evening. On Monday the barrels were respectively moved to the cellars of Messrs. Faber, and despatched to London. Both in London and Newcastle the samples which had been preserved by ice were always placed by the judges two days before the tests, under the same conditions of temperature to which ordinary consignments are required to be submitted. Now we come to the questions which were posed by Mr. Fjord: "Are the samples of butter preserved by refrigeration of less value, after they have remained two or three clays in an ordinary cellar, than the samples always preserved in the cellar and without refrigeration?" Again, "Is it necessary to admit that the refrigerated samples, which are described as 'good' immediately they are removed from the cold-room, lose their quality rapidly, and more rapidly than those samples which are preserved in the ordinary way?" For judging, the samples of butter were arranged so that the judges were not able to tell their age, where they were produced, or whether they had been preserved by means of ice. Each judge was required to give his opinion alone, and without communication with any one, and both judgment and price were made in accordance with the custom of the country. The classification was as follows: "Excellent quality," "Very good quality," "Good," "Good enough," "Mediocre." The prices are not given in the tables arranged by Mr. Fjord, who gives figures to indicate their proportion of value. The page 23 first series of experiments in 1885 was with butter obtained from two farms designated A and B. At each farm three days' butter was churned and divided into two lots. It was then immediately sent to the laboratory at Copenhagen under ordinary conditions, The temperature (Fahr.) of the cellar and of the cold-room was fallows :—

	Average.	Highest.	Lowest.
Cellar	59°	61°	56°
Cold-room	43°	45°	36½°

We shall now see the opinion given by the judges at each period. At the first farm, A, the three lots of butter were respectively forty-six, thirty-two, and thirty-nine days old. At the first testing each sample of the refrigerated butter was classed "Very good," and received the maximum number of points (100), while the figures placed against the samples merely kept in the cellar varied between 92.6 and 93.6, and were classed as "Good" only. The second test, a week afterwards, proved the refrigerated butter to be exactly as before, while the other had decreased to an average of 90.8 points, and was considered only as "Good enough." In the first instance the difference in the price of the two samples was 6.5 ore, and in the Second 9.8 ore (100 öre equal to 1s. 1½d.). From the second farm the samples were from thirty-two to thirty-eight days old. The preserved samples of butter in each instance and on each occasion were pronounced "Very good," and received 100 points, while the other samples were classed "Good" in each instance, and received an average of 94½ points at the first and 97.9 points at the second test. The difference in prices between the two samples was less than in Those of the first farm.

On farm C the five samples tested varied in age from nineteen to thirty days. The refrigerator-samples at each test were classed as "Very good," and received 100 points, while the ordinary samples received an average of 93½ points on the first and 89.2 points on the second test, each being described as "Good enough;" the differ- page 24 ence in price between the two samples being 5.6 öre on the first and 8.8 öre on the second occasion. In the test of the factory-butter the five samples refrigerated varied in age from eighteen to twenty-nine days; they were classed "Very good," and received 100 points on each occasion, while the other samples were only classed "Good" and received 95 points on the first and 94 points on the second test the difference in the prices ranging from 4.3 to 5 öre per pound. A similar table was also furnished showing the appreciation of each judge—and there were three in this instance. The refrigerated butters were found to be fifty-five times the best and five times equal, but in no instance inferior to the ordinary butters.

The third series, 7th to 13th July, 1886, was conducted in London. The butters were despatched on Wednesday from Denmark, reaching Newcastle on Thursday evening, and going on direct to London. The butters were from the same farm and factory, C and D. They varied from nine to fifteen days old in the case of C, and the London judges gave 100 points to the refrigerated and 93.9 to the other samples, showing a difference of 5.6 öre per pound; while the factory-butter of D of similar age also obtained 100 points for the refrigerated, and only 96½ points for the unpreserved samples. The cooled butter was found by the English judges to be ten times the best, five times equal, and three times inferior.

These figures are the result of fifteen tests, eight of which were first and seven second tests. There were, however, three other tests, in which one judge at Newcastle found these butters four times the best, thirteen times similar, and three times inferior; while one judge in London found them three times the best, three times similar, fad twice inferior. Thus fifteen of the eighteen tests by the judges were favourable to the preserved butter, while the three remaining tests give no decided superiority to one lot over the other. Upon the whole series of experiments the preserved butter received an average of 100 points, while the other received only 94.3 points, and in no instance was this classed as "Very good." Dealing with the difference in value upon the whole series, it appears that upon the first tests there was a difference of 5.3 per cent, and the second tests 6 per cent., while the differences in prices was 5.1 ore per pound on the first test, and 5-5 öre per pound on the second. Professor Fjord states that the experiments show that the butter preserved by refrigeration was superior to that kept in the ordinary manner, and, second, that the preserved butter, after removal from the refrigerator, Sept for a week in an ordinary cellar as well as butter which had not been refrigerated. He concludes that if refrigeration is to be Employed in practice, it would be necessary to provide apartments, not only in the boats, but in the dairies and railway-cars, and he believes also that the system will contribute to the renown of the Danish butter upon the English market. It is pointed out, however, that in the experiments there could be no control over occurrences which have as much, or even more, influence upon butter than age : such as the quality of the milk, the acidification of the cream, and the system of churning. It was always found throughout the experiments that the newest butter was the best. In 1879 M. Fjord, who made many observations with regard to temperature, found that the hold of a ship, even where it was below the level of the sea, was always warmer than either the water or the air. These experiments were repeated in July, 1886, when it was found that the temperature in the hold averaged 47.2°, in the sea 46.4°, and in the air 46.8°, while in the ice-boxes it averaged about 36.8° In a second series of observations made during a voyage from Copenhagen to Newcastle the results were very similar. The above details are condensed from a large number of reports which appeared at intervals, but they show in a practical and conclusive form that there are real and, indeed, substantial advantages to be obtained lithe judicious use of ice in the preservation of butter during its transit across the sea.