Process and apparatus for the acceleration of the ripening of spirits

A process for acceleration of the ripening of spirits is described, wherein the spirits are irradiated with ultrasonic radiation in the presence of wood staves which serve as a source of bouquet-improving additives. Through control of the irradiation parameters, reproducible results may be achieved on the industrial level. Circulation of the spirits within the irradiation chamber increases the uniformity of the irradiation. An apparatus is described for a continuous performance of the process on an industrial level.

BACKGROUND OF THE INVENTION 
This invention is in the field of the manufacture of alcoholic spirits. It 
is directed towards a process for the acceleration of the ripening or 
aging process through the use of ultrasonic treatments. 
The conventional procedure for ripening (aging) of spirits derived from 
grapes or grain has been storage over extended periods, in oak casks or 
metal tanks with oak inserts, of the distillates. This natural aging 
process is associated with substantial space requirements, and requires 
from many months to years to come to fruition. 
There are known methods for the acceleration of this natural aging process. 
One type of procedure involves treatment of the distillates with gases 
such as ozone, oxygen, nitrogen and mixtures thereof, often with 
simultaneous UV-treatments. Short periods of treatment in ball mills and 
heat treatments with electrical current have also been employed to 
accelerate the aging process. 
Ultrasonic treatment of the distillates in the presence of taste-improving 
additives is also a known procedure. Two patents describe this type of 
process, namely DD-PS No. 119,614 "Process for Quick-ripening of Spirits" 
and CH-PS "Ultrasonic Treatments in Casks". In both of these patents, 
ultrasonic treatment is used to accelerate both the chemical reaction 
involved with aging process and the extraction of bouquet-improving 
components from additives (e.g. wood). The disadvantage of the known 
processes lies in their lack of reproducible quality parameters, as the 
important technical aspects have not been isolated and controlled. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an industrial process 
for the ripening (aging) of spirits which insures accelerated aging with 
reproducible quality parameters. 
This is achieved through the treatment of the spirits in the presence of 
bouquet-improving additives, preferably wood, with an ultrasonic field of 
optimal operational frequency and with the greatest possible uniformity of 
intensity distribution over the total volume. 
To maximize the uniformity of the effect of the ultrasonic treatment over 
the entire volume of the spirits, the liquid is circulated by a pump 
through the irradiation chamber during the ultrasonic irradiation. The use 
of flow distributors, resonator chambers and special arrangements for wood 
staves used as bouquet-improving components aids in the achievement of 
this purpose. 
The process is effected in a closed system insulated from heat exchange. 
The process thus approaches an adiabatic one. 
As the amount of absorbed ultrasonic energy, and the corresponding rise in 
temperature, is dependent upon the degree of ripeness of the spirits, a 
direct temperature control is made possible through the use of an 
adiabatic process. The amount of energy absorbed is also dependent upon 
the particular spirit being treated. The accuracy of temperature selection 
should approximately reach .ltoreq..+-.1/10.degree. C. 
By acting upon the medium with an increased static pressure, through the 
use of compressed gas, the degree of efficacy of the ultrasonic treatment 
is improved. This pressure is also dependent upon the particular choice of 
medium. By regulating the pressure in relation on the ultrasonic 
intensity, the cavitation effect in the medium may be increased by a few 
orders of magnitude. 
It has been found that the inventive process results in considerable 
savings in time and yields products of very good quality within the 
following parameters: 
Ultrasonic frequency: 20-50 kHz, preferably 35 kHz 
Specific ultrasonic output: ca. 1.7 W/l 
Average ultrasonic intensity: ca. 0.5 W/cm.sup.2 
Wood surface area (dependent upon the particular spirit): 20-40 cm.sup.2 /l 
Circulation cycles: 3/hr. 
The given ultrasonic parameters have been optimalized and guarantee, in 
conjunction with the determination of the length of irradiation and amount 
of wood surface area required for any particular spirit, a controlled 
industrial process for the enderated ripening of spirits in conjunction 
with the extraction of bouquet-improving additives. 
The novel features which are considered as characteristic for the invention 
are set forth in particular in the appended claims. The invention itself, 
however, both as to its construction and its method of operation, together 
with additional objects and advantages thereof, will be best understood 
from the following description of a specific embodiment of the apparatus 
when read in conjunction with the accompanying drawings.

DESCRIPTION OF A PREFERRED EMBODIMENT 
The apparatus for carrying out the inventive process, according to a 
preferred embodiment, consists of two irradiation chambers 1 which are 
provided with capsule resonators 8. In order to avoid the periods of 
disuse which are technologically mandated by the irradiation process, the 
irradiation chambers are adapted so as to be alternately irradiated, as 
well as alternately filled and emptied. 
As may be seen from the drawing, the two irradiation chambers comprise part 
of an irradiation installation which may be extended by connection of 
additional chambers to the free connections 12 and 13. 
The irradiation energy is provided by an ultrasonic generator 22. The 
efficient function of the generator 22 is monitored by a measurement 
device 23 installed between the generator and the immersion resonators 8. 
As noted above, the narrow tolerance range of ultrasonic intensity 
required in order to maintain the quality parameters according to the 
inventive process is of great importance. The preferred embodiment is 
therefore additionally provided with a specially designed probe (not 
shown) for measurement of the irradiation intensity within the irradiation 
chamber. This may be advantageously introduced into the system through the 
hatch 9. This probe may be connected to the irradiation measurement device 
23 for periodic read-out of the measured values. 
In order to insure adiabatic operating parameters, irradiation chambers 1 
of the preferred embodiment are provided with a double casing. Insulating 
material 4 (e.g. a foam plastic) is provided for the space between the 
inner casing 2 and the outer casing 3. 
The irradiation chambers 1 are provided with covers which hermetically seal 
the system. The covers 5 are provided with holders 6 for the wood staves 7 
and the capsule resonators 8. These holders are designed to so orient the 
resonators 8 as to provide the greatest homogeneity of the irradiation 
field in the reaction medium 24, and to allow for irradiation of the wood 
staves 7 from all sides without interference. The resonators 8 are 
attached to conduits 25 provided with detachable hatch covers 18, allowing 
for the operation and control of each resonator independently of the 
others. Through the conduits 25 are introduced high-frequency cables 26 
which are connected to the resonators 8. 
Through the use of a pump 11, filling and emptying of the irradiation 
chamber via the inlet 21 and outlet 27 may be effected, as well as the 
circulation of the medium 24 during the irradiation process. In the 
conduit between the pump 11 and the inlet 21 flow rate measurement device 
19 is installed. The irradiation chamber 1 is provided with a baffle or 
deflector 10 to insure a uniform distribution of the medium 24 after its 
introduction through inlet 21. 
To control the pressure within the chamber 1, the cover 5 is provided with 
a pressure regulator 14. The taking of samples make be effected through 
stopcock 16. Recovery of the finished product may be effected through 
outlet 20. 
It will be understood that each of the elements described above, or two or 
more together, may also find a useful application in other types of a 
process and apparatus for the acceleration of the ripening of spirits 
differing from the types described above. 
While the invention has been illustrated and described as embodied in a 
process and apparatus for the acceleration of the ripening of spirits, it 
is not intended to be limited to the details shown, since various 
modifications and structural changes may be made without departing in any 
way from the spirit of the present invention. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic of specific aspects of this invention.