The Wisconsin tobacco reporter. (Edgerton, Wis.) 1877-1950, 1912-09-27
Effect of Heat on Curing Tobacco.


artificial condition; that is, it may be
applied only when the weather is un-
favorable, and in such way as to Gre
ate those temperature and moisture
conditions which would prevail in the
barn when the weather is just right for
curing. In this case the principal use
of the heat would be to prevent pole
sweat, and there is no reason to sup
pose that the result of the curing would
be different from that obtained in fav-
orable weather without the use of ar
tificial heat
On the other hand, the curing may
be forced by the use of heat so as to
hasten the process and materially af-
feet the quality of the cured leaf.
Bearing in mind that the rate Of drying
and the rate of curing may or may not
go hand in hand, it is plain that uni
formly satisfactory results in tobacco
curing can never be assured until ef-
hcient methods of regulating the tenn
perature and moisture in the barn are
followed. Artificial heat not only fur
nishes a means of securing the most
favorable temperatures for curing, but
when combined with ventilation also
constitute the only practicable means
Of controlling the humidity.
The rate of curing greatly increases
with a rise in temperature, and IN gen
eral more thorough curing is obtained
at higher temperatures, provided the
leaf is not dried too rapidly. 1t follows
that artificial heat where properly ap
piled is highly favorable to the quality
of cigar tobacco, for thorough barn
curing is essential to the best develop
ment of flavor, aroma and elasticity,
and, to a lesser degree, of color in the
sweating or fermenting process.
Artificial heat probably shows the
greatest effect on the color of the cured
leaf. Heat in the presence of sufficient
moisture greatly hastens the rate of
curing, but when used in conjunction
with ventilation it also greatly in
creases the rate Of drying. At given
temperatures the extent Of the changes
in color occurring during the curing are
controlled by the amount of moisture
in the leaf, so that the use of heat and
ventilation combined makes it possible
to control to certain extent the col
ors obtained. We have found in the
course of experiments that not only the
depth of the color, but also its charac-
ter, can be largely controlled by regu-
lating the temperature and ventilation.
Under the present method of curing
cigar wrapper tobacco, particularly
when the leaf is cured on the stalk, the
final color of SSthe bright wrappers is
normally clear cinnamon brown, free
from any greenish cast, but generally
showing more or less tendency toward
a reddish cast. The present demand is
for a wrapper of rather dull finish,
showing the lighter shades of brown
overlaid with faint olive, but absO-
lutely free from red. The recent rapid
development in the Connecticut valley
of the method Of harvesting by picking
the leaves from the plant is due pri-
marily to this demand for wrapper of
"Cuban finish" It has been demon
strated that artificial heat is an impOr-
tant factor in obtaining the best curing
with this type of leaf.
The two most important reasons why
artificial heat should be used in curing
practically all tobaccos are that (1) this
affords the only practicable means of
preventing the decay Of the leaf caused
by the excessive moisture during wet
weather, and ~ tobacco does not cure
properly at low temperatures, however
favorable the weather may be other
wise, a fact of special Importance in
northern tobacco districts. In the case
of cigar wrapper leaf another impor-
tant consideration is that proper con-
troll of the moisture in the barn, which
can only be accomplished by the use Of
heat combined with ventilation, is the
most efficient means Of securing desir-
able colors in the cured product.
Where no heat is used it frequently
happens that even after the curing is
largely completed wet periods of wealth
er bring the tobacco into such moist
condition that the color is greatly dark
ened and the quality of the tobacco
otherwise injured, while if cold wealth
er prevails during the curing the leaf
simply dries without otherwise develop
ing the desired properties of cured to-
bacco. The curing of cigar tobaccos
can never be placed on satisfactory
basis until the process has been rem
dered largely Independent of weather
conditions by the combined use of ar
tifcial heat and ventilation.
During the first stage of the curing,
in which the yellow color develops, the
principal value of the heat is to main
tain a favorable temperature in the
barn, and during this period care must
be taken to avoid too rapid drying. 1t
is evident that the barn must be rea-
sonably tight, so as to prevent the
rapid escape of the heat and moisture.
On the other hand, the barn must have
proper means of ventilation during wet
weather, otherwise the drying will be
checked and there will be danger of
pole-sweat when the second stage OF
fbo 10 ohp1
While it is true that the occasional
softening of the tobacco during the
second stage of the curing greatly i'm
proves its appearance, growers as a
rule do not fully appreciate the serious
injury to the color caused by allowing
the cured tobacco to become too damp.
Each time a cured leaf becomes damp
the color is not only darkened, but loses
its clearness and, besides, the tobacco
undergoes sort of cold sweat which
interferes with its normal fermenta-
tion in the packing house. This injury
can be easily avoided by drying out the
tobacco with artificial heat during wet
or damp weather.
The suggestions here outlined regard
ing the use of artificial heat in curing
have been worked out by experiments
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