26 MASS. EXPERIMENT STATION BULLETIN 336 



is unsuitable for preservation with sodium benzoate. 



11. Benzoated cider or grape juice will not make good vinegar or wine. 

 However, any alcohol which is present in the iuice will change to acetic 

 acid in spite of the preservative. It is therefore useless to attempt to 

 preserve fermented beverages by the use of sodium benzoate. 



12. Declare the presence of sodium benzoate and the amount added 

 in per cent by weight, on each container offered for sale. 



Experiments with sodium furacrylate and furoic acids showed them to be 

 inferior to sodium benzoate for preserving cider. 



Katadyn Treatment 



In this method the preservative used is silver in very minute amounts. 

 Equipment is very specialized and is obtainable on a rental basis only. 



The general procedure is to pass cider through silver electrodes which are 

 connected to a source of electric current. The cider makes an electrical contact 

 between the electrodes and definite amounts of silver are deposited in the cider 

 depending upon the strength of the current and the quantity of cider passing 

 between the electrodes during any given period of time. Definite information 

 regarding the operation of the Katadyn equipment is provided by the company 

 furnishing the equipment. 



Tests made here on a small scale show that the Katadyn process will suc- 

 cessfully preserve cider, but it does impart a metallic taste to the product, 

 which decreases during storage. Yeasts are more easily controlled by the 

 method than are molds, so that the Katadyn treatment combined with bottling 

 under a vacuum to inhibit mold growth, was found to be the most satisfactory 

 procedure. 



The use of this process in the treatment of cider is comparatively recent in 

 this country, so that no definite statement can be made regarding its prac- 

 ticability for large-scale production. 



Canning 



Plain cans should be used for canning cider instead of the enameled because 

 the latter perforate badly. The juice is merely filled into the cans, exhausted 

 for 15 minutes at 160° F. or preferably vacuumized to remove air, sealed, and 

 finally pasteurized for 15 minutes at 160° F. The product will keep for several 

 months in a cool place, but should not be held over from one year to the next. 



The main problem in the canning of cider is the elimination of oxygen from 

 the juice. It is the combined action of the oxygen and acid in the cider which 

 is believed to be responsible for the unusually corrosive action of cider on tin 

 cans. 



A procedure for the canning of cider recommended by Tucker, Marsh and 

 Cruess (25) is as follows: Place the cider in a vacuum tank, preferably glass 

 lined or of stainless steel, and apply a high vacuum of 28 to 29 inches about 20 

 minutes to remove dissolved and occluded oxygen. Then flash pasteurize the 

 cider for 30 to 60 seconds at 185° F. and run it directly into cans, filling to within 

 one-quarter inch of the top. Seal at once and cool immediately in cold water. 



Instead of flash pasteurizing, an alternate procedure would be to fill the cider 

 into cans after the vacuum treatment, leaving a good headspace. Then heat 

 the filled cans in water at 150° F. for about 10 minutes, seal the cans and process 

 at 150° F. for 30 minutes for small cans. 



In general, it is more desirable to concentrate the cider by vacuum and pre- 

 serve in class containers rather than to can the pure cider in tin cans. A some- 

 what inferior cider concentrate can also be prepared by open-kettle boiling. 



