Mr. J. Salleron has devised several apparatus which are destined to
render valuable service in the champagne industry. The apparently
simple operation of confining the carbonic acid due to fermentation in
a bottle in order to blow the cork from the latter with force at a
given moment is not always successful, notwithstanding the skill and
experience of the manipulator. How could it be otherwise?
Everything connected with the production of champagne wine was but
recently unknown and unexplained. The proportioning of the sugar
accurately dates, as it were, from but yesterday, and the measurement
of the absorbing power of wine for carbonic acid has but just entered
into practice, thanks to Mr. Salleron's absorptiometer. The real
strength of the bottles, and the laws of the elasticity of glass and
its variation with the temperature, are but little known. Finally, the
physical constitution of cork, its chemical composition, its
resistance to compression and the dissolving action of the wine, must
be taken into consideration. In fact, all the elements of the
difficult problem of the manufacture of sparkling wine show that there
is an urgent necessity of introducing scientific methods into this
industry, as without them work can now no longer be done.
No one has had a better opportunity to show how easy it is to convert
the juice of the grape into sparkling wine through a series of simple
operations whose details are known and accurately determined, so we
believe it our duty to recommend those of our readers who are
particularly interested in this subject to read Mr. Salleron's book on
sparkling wine. We shall confine ourselves in this article to a
description of two of the apparatus invented by the author for testing
the resistance of bottles and cork stoppers.
It is well, in the first place, to say that one of the important
elements in the treatment of sparkling wine is the normal pressure
that it is to produce in the bottles. After judicious deductions and
numerous experiments, Mr. Salleron has adopted for the normal pressure
of highly sparkling wines five atmospheres at the temperature of the
cellar, which does not exceed 10 degrees. But, in a defective cellar,
the bottles may be exposed to frost in winter and to a temperature of
25° in summer, corresponding to a tension of ten atmospheres. It may
naturally be asked whether bottles will withstand such an ordeal. Mr.
Salleron has determined their resistance through the process by which
we estimate that of building materials, viz., by measuring the limit
of their elasticity, or, in other words, the pressure under which they
take on a new permanent volume. In fact, glass must be assimilated to
a perfectly elastic body; and bottles expand under the internal
pressure that they support. If their resistance is insufficient, they
continue to increase in measure as the pressure is further prolonged,
and at every increase in permanent capacity, their resistance
diminishes.
[Illustration: Fig. 1.--MACHINE FOR TESTING BOTTLES.]
The apparatus shown in Fig. 1 is called an elasticimeter, and permits
of a preliminary testing of bottles. The bottle to be tested is put
into the receptacle, A B, which is kept full of water, and when it has
become full, its neck is played between the jaws of the clamp, _p_.
Upon turning the hand wheel, L, the bottle and the receptacle that
holds it are lifted, and the mouth of the bottle presses against a
rubber disk fixed under the support, C D. The pressure of the neck of
the bottle against this disk is such that the closing is absolutely
hermetical. The support, C D, contains an aperture which allows the
interior of the bottle to communicate with a glass tube, _a b_, which
thus forms a prolongation of the neck of the bottle. This tube is very
narrow and is divided into fiftieths of a cubic centimeter. A
microscope, _m_, fixed in front of the tube, magnifies the divisions,
and allows the position of the level of the water to be ascertained to
within about a millionth of a cubic centimeter.
A force and suction pump, P, sucks in air through the tube, _t_, and
compresses it through the tube, _t'_, in the copper tube, T, which
communicates with the glass tube, _a b_, after passing through the
pressure gauge, M. This pump, then, compresses the air in the bottle,
and the gauge accurately measures its pressure.
To make a test, after the bottle full of water has been fastened under
the support, C D, the cock, _s_, is opened and the liquid with which
the small reservoir, R, has been filled flows through an aperture above
the mouth of the bottle and rises in the tube, _a b_. When its level
reaches the division, O, the cock, _s_, is closed. The bottle and its
prolongation, _a b_, are now exactly full of water without any air
bubbles.
The pump is actuated, and, in measure as the pressure rises, the level
of the liquid in the tube, _a b_, is seen to descend. This descent
measures the expansion or flexion of the bottle as well as the
compression of the water itself. When the pressure is judged to be
sufficient, the button, _n_, is turned, and the air compressed by the
pump finding an exit, the needle of the pressure gauge will be seen to
redescend and the level of the tube, _a b_, to rise.
If the glass of the bottle has undergone no permanent deformation, the
level will rise exactly to the zero mark, and denote that the bottle
has supported the test without any modification of its structure. But
if, on the contrary, the level does not return to the zero mark, the
limit of the glass's elasticity has been extended, its molecules have
taken on a new state of equilibrium, and its resistance has
diminished, and, even if it has not broken, it is absolutely certain
that it has lost its former resistance and that it presents no
particular guarantee of strength.
The vessel, A B, which must be always full of water, is designed to
keep the bottle at a constant temperature during the course of the
experiment. This is an essential condition, since the bottle thus
filled with water constitutes a genuine thermometer, of which _a b_ is
the graduated tube. It is therefore necessary to avoid attributing a
variation in level due to an expansion of the water produced by a
change in temperature, to a deformation of the bottle.
The test, then, that can be made with bottles by means of the
elasticimeter consists in compressing them to a pressure of ten
atmospheres when filled with water at a temperature of 25°, and in
finding out whether, under such a stress, they change their volume
permanently. In order that the elasticimeter may not be complicated by
a special heating apparatus, it suffices to determine once for all
what the pressure is that, at a mean temperature of 15°, acts upon
bottles with the same energy as that of ten atmospheres at 25°.
Experiment has demonstrated that such stress corresponds to twelve
atmospheres in a space in which the temperature remains about 15°.
In addition, the elasticimeter is capable of giving other and no less
useful data. It permits of comparing the resistance of bottles and of
classifying them according to the degree of such resistance. After
numerous experiments, it has been found that first class bottles
easily support a pressure of twelve atmospheres without distortion,
while in those of an inferior quality the resistance is very variable.
The champagne wine industry should therefore use the former
exclusively.
Various precautions must be taken in the use of corks. The bottles
that lose their wine in consequence of the bad quality of their corks
are many in number, and it is not long since that they were the cause
of genuine disaster to the champagne trade.
Mr. Salleron has largely contributed to the improving of the quality
of corks found in the market. The physical and chemical composition of
cork bark is peculiarly favorable to the special use to which it is
applied; but the champagne wine industry requires of it an exaggerated
degree of resistance, inalterability, and elasticity. A 1¼ inch cork
must, under the action of a powerful machine, enter a ¾ inch neck,
support the dissolving action of a liquid containing 12 per cent. of
alcohol compressed to at least five atmospheres, and, in a few years,
shoot out of the bottle and assume its pristine form and color. Out of
a hundred corks of good quality, not more than ten support such a
test.
In order to explain wherein resides the quality of cork, it is
necessary to refer to a chemical analysis of it. In cork bark there is
70 per cent. of suberine, which is soluble in alcohol and ether, and
is plastic, ductile, and malleable under the action of humid heat.
Mixed with suberine, cerine and resin give cork its insolubility and
inalterability. These substances are soluble in alcohol and ether, but
insoluble in water.
According to the origin of cork, the wax and resin exist in it in very
variable proportion. The more resinous kinds resist the dissolving
action of wine better than those that are but slightly resinous. The
latter soon become corroded and spoiled by wine. An attempt has often
been made, but without success, to improve poor corks by impregnating
them with the resinous principle that they lack.
Various other processes have been tried without success, and so it
finally became necessary simply to separate the good from the bad
corks by a practical and rapid operation. A simple examination does
not suffice. Mr. Bouché has found that corks immersed in water finally
became covered with brown spots, and, by analogy, in order to test
corks, he immersed them in water for a fortnight or a month. All those
that came out spotted were rejected. Under the prolonged action of
moisture, the suberine becomes soft, and, if it is not resinous
enough, the cells of the external layer of the cork burst, the water
enters, and the cork becomes spotted.
It was left to Mr. Salleron to render the method of testing practical.
He compresses the cork in a very strong reservoir filled with water
under a pressure of from four to five atmospheres. By this means, the
but slightly resinous cork is quickly dissolved, so that, after a few
hours' immersion, the bad corks come out spotted and channeled as if
they had been in the neck of a bottle for six months. On the contrary,
good corks resist the operation, and come out of the reservoir as
white and firm as they were when they were put into it.
[Illustration: Fig. 2.--SALLERON'S APPARATUS FOR TESTING CORKS.]
Fig. 2 gives a perspective view of Mr. Salleron's apparatus for
testing corks. A reservoir, A B, of tinned copper, capable of holding
100 corks, is provided with a cover firmly held in place by a clamp.
Into the cover is screwed a pressure gauge, M, which measures the
internal pressure of the apparatus.
A pump, P, sucks water from a vessel through the tubulure, _t'_, and
forces it through the tubulure, _t_, into the reservoir full of corks.
After being submitted to a pressure of five atmospheres in this
apparatus for a few hours, the corks are verified and then sorted out.
In addition to the apparatus here illustrated, there is one of larger
dimensions for industrial applications. This differs from the other
only in the arrangement of its details, and will hold as many as
10,000 corks.--_Revue Industrielle._
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