GRAPES 
be salable the product must be clear, 
bright, and attractive. 
Methods of Preventing Fermentation 
Fermentation may be prevented in 
either of two ways: 
(1) By chemical methods, which con- 
sist in the addition of germ poisons or 
antiseptics, which either kill the germs 
or prevent their growth. Of these the 
principal ones used are salicylic, sul- 
phurous, boracic, and benzoic acids, for- 
malin, fluorides, and saccharin. As these 
substances are generally regarded as 
adulterants and injurious, their use is 
not recommended. 
(2) Mechanical means are sometimes 
employed. The germs are either removed 
by some mechanical means, such as fil- 
tering or a centrifugal apparatus, or they 
are destroyed by heat, electricity, ete. 
Of these, heat has so far been found 
the most practical. 
When a liquid is heated to a suffi- 
ciently high temperature all organisms in 
it are killed. The degree of heat re- 
quired, however, differs not only with the 
particular kind of organism, but also 
with the liquid in which they are held. 
Time is also a factor. An organism may 
not be killed, if heated to a high tempera- 
ture and quickly cooled. If, however, 
the temperature is kept at the same high 
degree for some time, it will be killed. 
It must also be borne in mind that fun- 
gi, including yeasts, exist in the grow- 
ing and the resting states, the latter 
being much more resistant than the for- 
mer. A characteristic of the fungi and 
their spores is their great resistance to 
heat when dry. In this state they can 
be heated to 212 degrees Fahrenheit with- 
out being killed. The spores of the com- 
mon mold are even more resistant. This 
should be well considered in sterilizing 
bottles and corks, which should be 
steamed to 240 degrees Fahrenheit for at 
least fifteen minutes. 
Practical tests so far made indicate 
that grape juice can be safely sterilized 
at from 165 degrees Fahrenheit to 176 
degrees Fahrenheit At this temperature 
the flavor is hardly changed, while at a 
temperature much above 200 degrees Fahr- 
L111 
enheit it is. This is an important point, 
as the flavor and quality of the product 
depend on it. 
This bulletin being intended for the 
farmer or the housewife only, the writer 
refers such readers as desire to go into 
the manufacture of grape juice in a 
systematic manner for commercial pur- 
poses to Bulletin 24, Bureau of Plant In- 
dustry, Department of Agriculture, on 
the same subject, this publication treat- 
ing only of methods that can be applied 
in every home. 
Home Manufacture 
Use only clean, sound, well-ripened 
but not over-ripe grapes. If an ordinary 
cider mill is at hand, it may be used for 
crushing and pressing, or the grapes may 
be crushed and pressed with the hands. 
If a light-colored juice is desired, put 
the crushed grapes in a cleanly washed 
cloth sack and tie up. Then either hang 
up securely and twist it or let two per- 
sons take hold, one on each end of the 
sack and twist until the greater part of 
the juice is expressed. Then gradually 
heat the juice in a double boiler or a 
large stone jar in a pan of hot water, so 
that the juice does not come in direct 
contact with the fire, at a temperature of 
180 degrees Fahrenheit to 200 degrees 
Fahrenheit; never above 200 degrees Fahr- 
enheit. It is best to use a thermometer, 
but if there be none at hand heat the 
juice until it steams, but do not allow it 
to boil. Put it in a glass or enameled 
vessel to settle for 24 hours; carefully 
drain the juice from the sediment, and 
run it through several thicknesses of 
clean flannel, or a conic filter made from 
woolen cioth or felt may be used. This 
filter is fixed to a hoop of iron, which 
can be suspended wherever necessary. 
After this fill into clean bottles. Do not 
fill entirely, but leave room for the liquid 
to expand when again heated. Fit a 
thin board over the bottom of an ordin- 
ary wash boiler, set the filled bottles 
(ordinary glass fruit jars are just as 
good) in it, fill in with water around the 
bottles to within about an inch of the 
tops, and gradually heat until it is about 
to simmer. Then take the bottles out 
