ILLUSTRATIONS. Page. 6 7 8 FIG. 1. Pasteurizer for apple juice... 2. Small pasteurizer for sterilizing apple juice in kegs 3. Apparatus for paraffining kegs. 4. Three views of wooden bung showing cotton plug and substitution of wooden skewer........ 4 6 UNFERMENTED APPLE JUICE. INTRODUCTION. The process of sterilizing, so extensively employed with other products, is not widely practiced with apple juice, probably because information is lacking as to methods of handling and the character of the product which may be obtained. In an extensive treatise on cider making by a British investigator, F. J. Lloyd, sterilization is not mentioned as a practical process. Warcollier states that no method of sterilizing the fresh must has yet been commercially used in France. A report from the American consul at Munich gives a method of sterilizing employed there. It applies, however, only to bottled apple juice. In America methods have been developed for the preparation of bottled apple juice, but they have received no general application. With a view to gaining information as to methods of sterilizing apple juice, experiments were conducted during the season of 1906 © in Nebraska and continued during 1907 at Washington, D. C. Apple juice is found to be a product which it is easy to sterilize, while conserving to a large extent the delicious flavor of freshly expressed juice. The process is inexpensive and capable of application on a small or large scale. If desired, the product may be carbonated before use, and when so treated closely resembles apple cider in which the natural fermentation is just beginning. The term "sterilization" as used herein indicates that the fruit juices treated as described do not develop any bacterial or fungous growths within the period usually elapsing before their consumption. The temperatures employed, however, are those commonly used in the process termed "pasteurization." The various phases of the investigation will be discussed, experiments having been made with wooden, tin, and glass containers, with different methods of clarifying and carbonating, and with the use of preservatives. STERILIZATION OF APPLE JUICE. IN WOOD. These experiments were made to develop a method for sterilizing apple juice in wooden containers so that it might be marketed with a Report on the Results of an Investigation into Cider Making, etc., 1893-1902. London, 1903. Les méthodes scientifiques dans l'industrie du cidre. Rev. gén. sci. pures et appliquées, 1907, 18:778. c Yearbook of the U. S. Department of Agriculture, 1906, p. 239. out the use of chemical preservatives, such as benzoate of soda, which is commonly used at present. Aside from hygienic reasons, experiments (see p. 19) have shown that the use of benzoate of soda is far from being a satisfactory means of preserving apple juice. The objections urged against sterilizing are (1) that a "cooked" taste is added to the juice, greatly injuring the flavor, and (2) that it is impracticable to hold the juice sterile for more than a limited period. These objections have been met. The investigations here reported demonstrate that only a slight cooked taste is produced by the heat STEAM INLET treatment required and that it is a simple matter to protect the juice from inoculation after sterilizing. BRASS GROUND © VALVE -12 OUTLET FOR SPIRAL RIVETED 14 BLOCK TIN COIL ASBESTOS PIPS EXPERIMENTS WITH BARRELS. In the experiments of 1906 on sterilizing in barrels, it was found that they could be successfully used as containers when it was desired to keep the juice sweet for a few weeks. In one experiment two 50-gallon barrels were thoroughly cleaned, well steamed, and filled with the juice heated to between 149° and 158° F. (65° and 70° C.). In sealing a cask which is full of hot liquid, air should be allowed to enter during cooling to destroy the vacuum caused by the contraction of the liquid. Unless this is done, a severe strain is put on the cask, greatly increasing the danger of contamination. In this experiment, instead of at first driving in bungs to close the barrels, clean cotton plugs were used. When the casks and contents were cool, the plugs were removed and wooden bungs which had been sterilized by soaking in alcohol were quickly inserted. The juice kept for ten days without showing fermentation. TO STEAMe STUFFING Bar BRASS GROUND JOINT UNION INLET FOR "JUICE FIG. 1. Pasteurizer for apple juice. In this experiment the pasteurizer shown in fig. 1 was employed and proved to be a very useful machine, capable of heating the juice with perfect control of temperature at any desired rate up to several hundred gallons per hour. This pasteurizer was built for about $50. a Loc. cit. EXPERIMENTS WITH KEGS. Further experiments on sterilizing in wood were made during the season of 1907-8, and the results show that wooden containers can be successfully employed for fairly long periods of time. In these experiments, 10-gallon kegs made of No. 1 white-oak stock, costing $1.05 FIG. 2. Small pasteurizer for sterilizing apple juice in kegs. each, were used. A pasteurizer of smaller size was employed, similar to the one shown in fig. 1, but built of lighter material and costing about $12 (fig. 2). The results were satisfactory and demonstrate that this model will be found useful in work conducted on a small scale. The kegs were prepared for use as follows: They were paraffined on the outside by dipping in a bath of melted paraffin which was heated to about 120° C. (248° F.) by means of a steam coil. The arrangement is shown in fig. 3. Steam was run into the keg for about three minutes, when it was allowed to cool somewhat, and sulphured by lowering into each keg a small crucible filled with burning sulphur. The kegs were allowed to stand closed overnight, and in the morning just before filling they were steamed out for three minutes and well rinsed, removing practically all of the sulphur. It was found that a longer period of steaming melted the paraffin on the outside of the kegs. The juice was heated by running through the pasteurizer at from 65° to 70° C. and was delivered directly into the kegs. As each was filled, it was closed in the following way: A wooden bung which had been paraffined and then dipped in alcohol was placed in the bunghole. The quarter-inch hole in the center of the bung was stuffed with cotton and the bung was driven into the keg (fig. 4a). 28 FIG. 3.-Apparatus for paraffining kegs. Then the cotton plug was removed and another plug immediately inserted and saturated with alcohol. The cotton is stuffed into the bung before the bung is inserted in order to prevent the entrance of organisms while it is being driven in, and is replaced by a fresh plug of cotton afterwards, because it usually becomes saturated with juice during the driving. This plug of cotton, sterilized by alcohol, prevents access of organisms during cooling, the air sucked in on account of the contraction of the juice on cooling being filtered through the cotton. When the juice had cooled the cotton plug was cut off at the surface of the bung, the portion of the plug remaining was wet again with alcohol, and a wooden skewer, fitting the hole in the bung closely, was sterilized by soaking in melted paraffin, then in alcohol, and driven into the hole, forcing the cotton plug out. In this way the cotton plug was replaced by a sterilized wooden plug without any chance for the entrance of organisms. The skewer was then sawed off even with the surface of the bung and smoothed over by a little melted paraffin (fig. 4, b and c). Forty 10-gallon kegs were filled in this way, and of these 22 were kept unopened for more than six months, the juice in the remaining kegs being used for other purposes. The juice was prepared from |