Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE FOR MEASURING ALCOHOL CONTENT OF A FERMENTING LIQUID
FIELD OF THE INVENTION
The present invention relates to quality control in the production of
fermentable
liquids and more specifically, the brewing process. In particular, to evaluate
the amount
of fermentable sugar in the liquid before fermentation and to evaluate the
amount of
sugar converted to alcohol throughout the fermentation process.
BACKGROUND OF THE INVENTION
Strict quality control is an essential component of the brewing process and is
required to ensure that the mashing and fermentation processes proceed
successfully.
Mashing is the process whereby malted barley is crushed and infused with hot
water
which hydrates the malt and releases the starch granules contained in the
barley kernel
endosperm. The mash is performed at a temperature of 65-68 C which is the
active
temperature range for several enzymes responsible for breaking down the starch
polymer into fermentable sugars. The principle enzymes activated are alpha-
amylase
which produces a variety of sugars and dextrins, beta-amylase which produces
maltose
and alpha-glucosidase which deaves maltose and larger sugars into glucose.
Each
enzyme has a specific optimal temperature range and by adjusting the
temperature and
activation time at each temperature, the brewer selects the sugar profile of
the wort [1].
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Assuming the starch is completely converted to sugars, after sparging and
filtering, the wort consists of a water and sugar solution. The specific
gravity of the wort
increases with the sugar content. Each type of beer has a target specific
gravity range
before fermentation which corresponds to the flavor profile of the beer.
Therefore by
measuring the specific gravity of the wort prior to fermentation, the brewer
can
determine if the mashing process was successful or if further mashing or
dilution with
water is required.
Often, recipes will specify a degree Plato range for the wort rather than a
specific
gravity range. The Plato scale is based on empirical data which correlates the
percentage of sucrose by weight in an aqueous solution to the specific gravity
of the
solution. In reality, the sugar profiles of beers are very complex and there
are many
different sugars present which have slightly different densities than sucrose
leading to
deviations from the Plato scale. However due to the lack of a more appropriate
standard, it is assumed that the variation in densities due to other sugars is
negligible
and the wort can be evaluated by assuming a pure sucrose sugar profile. By
fitting a
mathematical model to the empirical data, the degrees Plato can be calculated
from
specific gravity using equation 1 [2]:
258.6
P -= 1 (eq.1)
Fermentation is the process whereby the yeasts metabolize sugars in the
wort and produce alcohol and carbon dioxide as described in equation 2; as a
result, the
specific gravity of the liquid decreases as the fermentation progresses.
C6I-11206 4- Yeast 4 2C2H50H 2CO2 (eq.2)
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The alcohol content of the fermenting liquid can therefore be determined by
taking density measurements of samples before and after fermentation. The
percentage
of alcohol by volume can be calculated using the equation 3 [4
0..05x(OG-FG)
%ABV = FG 0389 X 100% (eq.3)
Whereby OG and FG are the original and final specific gravities, respectively.
The coefficient of 1.05 represents the ratio of the mass of carbon dioxide
produced for
the same mass of ethanol produced (Mco2/MEthand). The number 0.789 is the
specific
gravity of ethanol at room temperature (20 C). Beer recipes have a target
alcohol by
volume percentage. Therefore by measuring the density of the fermenting liquid
and
calculating the alcohol percentage, the brewer can assess the progression of
fermentation and whether the target alcohol percentage was obtained
successfully.
Conventionally, brewers use hydrometers to measure the specific gravity or
degrees Plato of beer. The hydrometer device consists of a weighted bulb
inside a stem
with a numbered scale. The bulb floats in the liquid and is partially
submerged so that
liquid surface is located at a position on the numbered scale which
corresponds to the
specific gravity or degrees Plato of the liquid. The brewer can then perform
calculations
to convert the hydrometer reading from specific gravity to degrees Plato or
Vice Versa,
if necessary. The brewer can record the specific gravity reading before
fermentation and
use another specific gravity reading during or after fermentation to calculate
the
percentage of alcohol in the liquid [4].
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There are several disadvantages regarding the use of hydrometers. The
circumference of the hydrometer stem is reduced to the smallest possible value
in order
to minimize errors caused by surface tension effects [4]; this results in a
very small
scale which is often difficult to read. Hydrometers must also be periodically
calibrated
which is a difficult task for an amateur brewer.
Additionally, there are several disadvantages to this manual record keeping
and
calculation approach. First off, the brewer must perform tedious calculations
by hand
which is undesirable especially for amateur brewers who are new to brewing and
do not
fully understand the scientific principles. Secondly, the brewer must manually
record the
specific gravity reading before fermentation and keep track of this record in
order to
calculate the alcohol percentage after fermentation weeks later. When brewing,
there
are so many other parameters to keep track of that a simple specific gravity
reading
from weeks prior can be easily lost.
There have been numerous developments made in this field. One of such
developments was improving the readability of hydrometers by implementing a
magnifying element into the material making up the stem wall [4]. However,
even with
this improvement there is still a lack of automation and simplicity for
hydrometer users.
Other developments include various methods for measuring density. Portable
refractometers have been developed for measuring the density or sugar
concentrations
of liquids. The wavelength of light bends or refracts to a certain degree
depending on
the composition of the liquid and this can be correlated to density [5]. A
device
consisting of an ultrasonic transmitter and receiver has been developed which
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correlates the speed of sounds through the liquid with density. With
measurements
taken at different time points, the device can also measure the degree of
fermentation
[6]. Another device was developed which calculates density from the
differential
pressure using pressure sensors placed at two different heights in a tank [7].
These
novel methods of measuring density are precise but intrinsically complex and
expensive
and only meant to be implemented at an industrial scale. There is still a need
for such a
device which would be affordable for smaller scale brewers.
A device designed to measure the weight of a medium in a tank incorporating a
level measuring device, a density measuring device and an evaluation unit has
also
been developed [8]. However, this device uses density and volume to calculate
weight
rather than using volume and weight to calculate density and again it is
intended to be
implemented at an industrial scale.
While the aforementioned references may be adequate for their intended
purposes, there is still a need for a device that is simple to operate, cost
effective and
capable of measuring specific gravity of a liquid and digitalizing the
information so that it
can be stored electronically and calculations can be performed automatically.
SUMMARY OF THE INVENTION
With the foregoing in view, it is an object of the present invention to
provide a
device which is capable of measuring the weight and volume of a fermenting
liquid and
calculate the specific gravity, degrees Plato and percentage of alcohol. In
order to
achieve the aforementioned object, a device is provided comprising of the
components
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defined in Claim 2. The fermenting liquid to be analyzed is poured into the
vessel and
the user reads the volume measurement from the scale on the vessel. The user
inputs
the volume reading from the scale using the numerical keypad on the device.
The built
in weight scale measures weight of the vessel containing the fermenting liquid
less the
weight of the empty vessel. The central processing unit computes the specific
gravity of
the liquid and displays the value on the screen. The central processing unit
also
converts the specific gravity to degrees Plato using equation 1 and displays
the value
on the screen. The user then chooses to save the information to a memory index
using
the digital memory component of the device or compute the percentage of
alcohol by
volume. If the latter option is selected, the user must select the memory
index for which
the specific gravity reading before fermentation is stored; the device then
computes the
percentage of alcohol by volume using equation 3 and the result is displayed
on the
screen.
A thermocouple, built into the wall of the vessel, measures the temperature of
the
fermenting liquid. When calculating the percentage of alcohol by volume, the
central
processing unit applies a correction factor to the specific gravity
measurement of the
liquid taken before fermentation so that it is properly compared to the
specific gravity
measurement taken after fermentation.
Additional features and advantages of the present invention will become more
apparent from the detailed description that follows, taken in conjunction with
the
accompanying drawings.
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Brief Description of the Drawings
FIG. 1 illustrates a system for measuring fluid density, alcohol, and sugar
content
according to an exemplary embodiment of the present invention.
FIG. 2 illustrates the user interface according to the present invention.
FIG. 3 illustrates the graduations on the fluid measuring vessel to determine
the volume
of fluid present within the vessel of the present invention.
FIG. 4 illustrates the locking mechanism located at the base of the vessel
containing the
fluid which attaches it to the scale component.
FIG. 5 illustrates the fluid vessel possessing a thermocouple at its base to
measure fluid
temperature.
FIG. 6 illustrates a process flow chart describing the decision course of the
central
processing unit according to the present invention.
Description
FIG. 1 illustrates a system for measuring fluid specific gravity according to
an exemplary
embodiment of the present invention. As shown, the vessel at position 1
encloses the
fermentation fluid whose properties are to be evaluated. The vessel us
attached to the
scale base 3 at region 2 by an interlocking mechanism. The central processing
unit, the
storage memory and the weight measuring hardware are located within region 4
which
is controlled by the operator interface 5.
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One possible application of this method is to measure the specific gravity of
beer during
its fermentation process to obtain alcohol percent composition and degrees
Plato value.
FIG. 2 illustrates the user interface according to the present invention. The
device is
powered by pressing the power button 14. Buttons 9 and 10 allow the operator
to clear
and enter data into the CPU, respectively. The keypad allows the operator to
modify
values in region 8. The specific gravity of the fluid is displayed in region
11. The
calculated degrees Plato and alcohol percentage are displayed in regions 12
and 13,
respectively. As shown in the figure, memory 1, 6 stores data from the fluid
before it
undergoes the fermentation process and memory 2, 7 stores data from the fluid
after it
undergoes the fermentation process.
FIG. 3 illustrates the graduations on the fluid measuring vessel to determine
the volume
of fluid present within the vessel of the present invention. The vessel 15
possesses
graduations 16 indicating volume values of the vessel. Region 18 indicates the
region
where the vessel is attached to the base of the scale 17.
FIG. 4 illustrates the locking mechanism located at the base of the vessel
containing the
fluid which attaches it to the scale component. As shown in the figure, the
vessel 19 is
attached to the base of the scale 21 using threads 20 to screw the vessel into
the base
of the scale. This would secure all the components to the apparatus in figure
1 but
would also allow for hardware repairs if needed.
FIG. 5 illustrates the fluid vessel possessing a thermocouple at its base to
measure fluid
temperature. Specific gravity of the fluid in the vessel is subjected to
change with
variations in temperature. Changes in temperature may then negatively
influence the
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calculated parameters and diminish the accuracy of the results. Means of
accounting for
variations in environmental conditions may be accomplished by adding a
thermocouple
to measure the fluid properties. Certain calculation parameters would then be
adjusted
by the CPU to obtain accurate fluid property results. The volume that the
thermocouple
occupies within region 22 would be accounted for the in the CPU calculations.
FIG. 6 illustrates a process flow chart describing the decision course of the
central
processing unit according to the present invention. As shown in the figure,
the volume
value of the first fluid is inputted by the operator and accessed by the CPU,
25. The
weight measurement of the first fluid is directly taken by the CPU from the
scale 26. The
CPU uses the implemented algorithm to calculate the specific gravity of the
first fluid as
well as its Degrees Plato, 27. The values are stored in memory 1, 26 along
with being
displayed in the interface to the operator 28. The volume value of the second
fluid is
inputted by the operator is accessed by the CPU, 31. The weight measurement of
the
second fluid is directly taken by the CPU from the scale 32. The CPU uses the
implemented algorithm to calculate the specific gravity of the second fluid,
the Degrees
Plato as well as its alcohol percentage, 30. The values are displayed to the
operator in
the interface 33.
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NON-PATENT CITATIONS
[1] J. J. Palmer, How to Brew, Colorado: Brewers Publications, 2006.
[2] A. Lewis, "The Home Brewer's Answer Book," North Adams, MA, Storey
Publishing,
2007, p. 60.
[3] R. Peros, "BrewMoreBeer.com," 7 May 2010. [Online]. Available:
http://www.brewmorebeer.com/calculate-percent-alcohol-in-beer/. [Accessed 3
November 20131.
PATENT CITATIONS
[4] G. J. Waite, "Specific Gravity Device". Canada Patent CA 02422503, 18 03
2003.
[5] H. Amaniya, Y. Amagasa, K. Takeshi and M. Mitsuru, "Portable
Refractometer".
Europe Patent EP 1686365 B1, 27 January 2005.
[6] J. A. Graham, J. C. Mitchinson and . D. M. J. Skrgatic, "Measurement of
specific
gravity". Global Patent WO 1987002770 Al, 29 October 1985.
[7] A. C. Cardoso, . A. D. C. Filho, . L. C. Geron, F. d. B. P. Machado, . G.
Selegatto, . J.
C. d. 0. Sobrinho and C. S. Verissimo, "System and method for determining a
density of a fluid". United States of America Patent US 5827963 A, 31 May
1996.
[8] A. Kahlert, J. Kroger, S. Lopatin and P. Prokesch, "Device for determining
and/or
monitoring the weight of a medium in a container used in measuring and
automation
systems comprises a level measuring unit, a density measuring unit and an
evaluation unit". Germany Patent DE 102005050400 Al, 19 October 2005.
[9] H. Weissler, "Brewing Calculations," in Handbook of Brewing, New York,
Marcel
Dekker, Inc., 1995, pp. 643-651.
