June 15,1925 Environ ment and Chemical Composition of Grape Juices 1141 
Analytical Methods 
The samples preserved by addition 
of bichloride of mercury were used for 
sugar determinations only. No correc¬ 
tion was necessary for the amount of 
HgCl 2 used (0.25 gram for 250 c. c. of 
juice). 
Reducing sugars were determined by 
clarification with neutral lead acetate, 
removing the excess lead with potas¬ 
sium oxalate, and employing the 
Munson and Walker method, titrating 
the cuprous oxide with N/20 KMn0 4 
after solution in ferric ammonium 
sulphate. The results are expressed as 
invert sugar or as invert sugar in 
presence of sucrose accordingly as 
sucrose was found to be present or 
absent. Total sugars were determined 
by inversion of a portion of the clarified 
solution and application of the same 
method. Sucrose was determined by 
difference of the figures before and 
after inversion. Duplicate determin¬ 
ations were run in all cases and were 
repeated when the amounts of KMn0 4 
required for titration of the copper 
differed by more than 1 per cent. 
Acidity, total astringency, and astrin¬ 
gent nontannins were determined by 
the same methods employed in the 
field determinations. 
Total solids were determined upon 
special samples used only for that 
purpose. Before being opened the 
bottle was shaken vigorously to bring 
the sediment into suspension, and 
duplicate 10 c. c. samples were pipetted 
with a wide-tipped pipette into flat- 
bottomed 10 cm. Petri dishes. Suffi¬ 
cient distilled water was added to each 
dish to spread the liquid in a uniform 
film over the bottom, the dishes were 
brought almost to dryness on a water 
bath, and the drying was completed 
in a vacuum oven at 90° C. 
ANALYTICAL DATA 
The analytical data are given in 
Tables III and IV. 
Discussion of the Analytical Data 
Table III brings together all the 
analytical data for 49 varieties which 
fruited yearly during the 5-year period 
while Table IV presents similar data 
for 16 varieties which did not fruit 
regularly during this time. Some of 
the outstanding facts shown by the 
figures maj^ be discussed somewhat in 
detail. 
SUGAR CONTENT 
The range of variation in sugar con¬ 
tent during the 5-year period shows 
large differences among the varieties, 
ranging from 1.47 per cent in Woodruff 
to 8.04 in Jefferson and Delaware. In 
two varieties the range of variation is 
between 1 and 2 per cent of sugar; in 
twenty-five it is 2 to 4 per cent; in 
sixteen, 4 to 6 per cent; in three, 6 to 8 
per cent; and in two the variation 
exceeds 8 per cent. It might be 
assumed that a narrow range of varia¬ 
tion in sugar content indicated perfect 
adaptation to the local conditions while 
a wide range indicated that the variety 
was out of its proper environment or 
subject to a variable factor such as 
disease attack. This assumption is 
scarcely borne out by the facts, since 
among the varieties showing a range of 
variation of 3 per cent or less are 
Concord, Cynthiana, Elvira, Martha, 
and Woodruff, while those showing 
a range of 6 to more than 8 per cent are 
Agawam, Brighton, Delaware, Eume- 
lan, Jefferson, and Nectar. Of these, 
Cynthiana is the only distinctively 
Southern variety, Nectar is the only 
one of the group lacking in vegetative 
vigor and resistance to disease, and 
Woodruff is the only one which is 
susceptible to injury by spraying or 
fails to ripen its fruit uniformly and 
with characteristic color. The others 
are varieties which are well adapted to 
the Vineland region, as shown by their 
vigor and productiveness and freedom 
from insect or fungus attack. The 
explanation of the wide range of varia¬ 
tion in the six varieties last named 
would appear to be fairly clear. All 
are midseason or late maturing at 
Vineland. Two years, 1919 and 1923, 
were exceptionally favorable for the 
maturing and ripening of long-season 
varieties, and the maximum sugar con¬ 
tent for four of these occurred in 1923, 
for the other two in 1919. The maxi¬ 
mum for three of the six varieties 
occurred in 1922, the least favorable 
year of the period. Additional evi¬ 
dence that these wide variations in sugar 
content are attributable to the varia¬ 
tions in seasonal conditions will be 
brought out in the subsequent dis¬ 
cussion. 
With the exception of the six varie¬ 
ties just mentioned, the range of varia¬ 
tion in sugar content is from 1 to 6 per 
cent. Hartmann and Tolman {27) an¬ 
alyzed samples of 104 commercial 
juices of Concord grapes, collected at 
factories during the season of 1912, 
1913, and 1914, and representing the 
Hudson River district, the Chatauqua 
belt, and the Lake Erie district. These 
samples had sugar contents ranging 
from 11.41 to 17.53 per cent, a range of 
6.12 per cent. Alwood and his col¬ 
laborators {2, 3, 6, 7) made analyses 
pf a very large number of varieties of 
