24 MASS. EXPERIMENT STATION BULLETIN 336 



Freezing 



If cider is frozen solid in closed containers and held at a temperature of 10° F. 

 or lower, it may be held from one season to the next without any appreciable 

 change in its flavor. 



The container in which the cider is to be frozen, whether it be a barrel, glass, 

 or cardboard container, should not be filled more than three-quarters to four- 

 fifths full, since the cider expands during the freezing process. The container 

 should be covered to prevent the juice from acquiring foreign flavors during 

 freezing. 



Freezing does not destroy the yeasts and molds so that after the cider is 

 thawed out it is almost as perishable as freshly pressed cider. 



Sufficient time should be allowed for the frozen cider to thaw out after it is 

 removed from storage. If the containers are not too large, they can be set in 

 water and shaken occasionally. Large containers require as long as 24 hours to 

 thaw out. 



Cider may be kept fresh for several weeks by simply storing at temperatures 

 of 32° to 36° F. Fermentation ultimately sets in, however, and cold-storage 

 temperatures cannot be relied on to preserve the cider indefinitely. Cider will 

 keep much longer in cold storage if it is chilled immediately after pressing. 



Pasteurization 



This term is applied to any method of heat treatment in which the food prod- 

 uct is heated to a temperature less than the boiling point of water (212° F.). 



It must be understood that pasteurization treatment does not always sterilize 

 the product treated. In non-acid products such as milk, the object of pas- 

 teurization is to destroy certain disease-producing microorganisms without 

 necessarily eliminating spoilage organisms. In an acid product such as cider 

 or wine, the treatment is employed to destroy or inactivate spoilage organisms 

 such as yeasts and molds, since disease-producing microorganisms are not 

 ordinarily found in acid products. 



The temperature employed depends upon the length of time that the product 

 is heated. Heating the product to a high temperature for a short time is called 

 "flash" pasteurization; heating at a low temperature for a longer period, 20 

 or 30 minutes, is called the "holding" method of pasteurization. 



Flash Pasteurization 



There is special flash pasteurization equipment made for the dairy industry 

 which can be used to process cider. However, a small coil pasteurizer made 

 from aluminum tubing has been used successfully to flash pasteurize small lots 

 of cider here. The cider is fed by gravity through one coil which is immersed 

 in a tank of water heated to the desired temperature. The j uice then flows through 

 a second coil which is surrounded by cold water. A thermometer inserted through 

 an opening in a bronze T-joint joining the two coils indicates the temperature 

 of the cider after it passes through the heated coil. The flow of the cider should 

 be regulated so that the cider is heated to 185° F. before it reaches the cooling 

 coil. The latter should cool the juice down to 140° F. Bottles and caps should 

 be treated to kill any yeasts or molds on them. Boiling the bottles and caps 

 for a minute is a good method of eliminating the spoilage organisms. The 

 bottles should be filled as full as possible when bottled from a flash pasteurizer. 



Holding Method of Pasteurization 



In this method the clean bottles are filled with cider heated to 130° to 140° F., 



