6 BULLETIN 241, U. S. DEPARTMENT OF AGRICULTURE. 
receiving a heat treatment much longer than necessary, which may 
injure the flavor. Another objection to casks is that the color and 
flavor of the juices are injured by the gradual solution of extract 
from the walls of the contamer. Wooden casks can not, therefore, 
be generally recommended as containers for fruit juices. 
Tin CANS. 
Juices may be far more easily sterilized in cans than in wooden 
casks. Cans, however, can not at the present time be generally recom- 
mended, as experiment shows that the tin is constantly dissolv- 
ing in the juice, even when the type of can designated as ‘‘enamel 
lined”’ is used. There is consequent injury to color, in case of deli- 
-cately tinted juices, and the flavor also is often injuriously affected. 
The ease with which juices are sealed and sterilized in tin cans, 
however, makes it seem probable that they may be successfully used 
in aoncial instances for storage of sterilized juices, during oe 
periods at least. 
TEMPERATURES AND TIMES OF HEATING. 
In cooking the fruit pulp in the kettle the temperature does not 
exceed 95° C. (203° F.) during the time ordinarily required to reduce 
the fruit to a pulp, usually less than 5 minutes. In heating juice 
to be transferred to hot carboys the temperature should be carried 
up to from 85° to 90° C. (185° to 194° F.). The sterilizing temper- 
atures here recommended for general use in preparing fruit juices are 
higher than those used in the earlier part of the experimental studies 
to be described later. In this work it was found that while at 
times complete sterilization was effected at a temperature of 70° C. 
(158° F.), or even lower, upon other occasions mold developed. Em- 
ployment of higher temperatures resulted in almost wholly eliminat- 
ing the difficulties of mold growth in juices heated in bottles. 
A temperature of at least 80° C. (176° F.) is recommended for all 
fruit juices sterilized in bottles, allowing, when starting with cold 
juice, half an hour for the juices to attain bath temperature, and 
keeping the bottles at this point for at least half an hour. Where it 
is found that no injury to flavor results, this temperature may be 
increased with advantage. Usually merely filling the bottles or fruit 
jars with the boiling-hot juice and sealing them immediately is sat- 
isfactory. An exception, however, to this treatment is found in the 
case of lemon juice, the flavor of which is much injured by heating 
to 80° C. This juice is easily sterilized, without serious injury to the 
flavor, by being heated to 70° C. for half an hour, allowing half an 
hour for the juice to attain bath temperature. 
With juices sterilized in carboys the situation is less satisfactory, 
as infection with molds often occurs when all of the precautions 
already described have been taken. The method of sterilizing 
