JP6966787B2 - Alcohol concentration measurement method - Google Patents

Description

The present invention relates to an alcohol concentration measuring method, and more particularly to an alcohol concentration measuring method that does not require a distillation step for obtaining a distillate.

Regarding the measurement of the alcohol concentration of alcoholic beverages, since the alcohol content is contained in other than distilled alcoholic beverages, the alcohol concentration of the sample without the extract, that is, the distillate obtained by distilling the sample once is obtained.

Distillation methods include direct-fire distillation, steam distillation, and the like. For example, when steam distillation is used, 100 ml (15 ° C) of the sample is weighed and steam distillation is performed. By collecting the distillate up to 98 ml, measuring it to 100 ml (15 ° C), and determining the alcohol content% (v / v%) of the distillate from the density, the alcohol content% (v / v%) of the sample is obtained. ) Can be obtained. As a result, an alcohol concentration excluding the influence of the extract component can be obtained. At this time, as a matter of course, the extract component remains in the residue.

On the other hand, since distilled liquors such as whiskey and brandy have a small or almost zero extract content, there are some that can omit the above-mentioned distillation step to determine the alcohol concentration. That is, there are some that allow a method of directly obtaining the alcohol concentration from the weight of a predetermined volume of distilled liquor at a predetermined temperature (15 ° C.).

In the case of the above distillate or distilled liquor, a table for converting the alcohol concentration from the density is prepared for calculating the alcohol concentration of the sample itself (Prescribed Analysis Method Table 2: Presented by the National Tax Agency).

National Tax Agency Prescribed Analysis Method 3-7

When it is necessary to once distill the sample to obtain a distillate, the distillation step requires time and strict volume measurement under strict temperature control is required. In addition, since the sample cannot be completely recovered as a distillate by the distillation method, the obtained value contains an error of -0.3 to -0.1 vol% (see Table 2 below).

In addition, distilled liquor (for example, whiskey, brandy) that is stored in barrels has an extract content eluted from the barrel along with the pigment during storage even if it is distilled liquor, and the measured value is at most -0.5 vol%. Due to the error, it is obligatory to measure the alcohol concentration by measuring the density after distillation.

The present invention has been proposed in view of the above-mentioned conventional circumstances, and provides a method for obtaining a highly accurate alcohol concentration even for alcoholic beverages containing an extract without going through a distillation step for obtaining a distillate. The purpose is to do.

The National Tax Agency Prescribed Analytical Method 3-7 presents a method for calculating the extract concentration (specific gravity) E in the distillation method.

E = (SA) x 260 + 0.21 ... (1)
S: Sample specific gravity, sample density (15 ° C) / pure water density (4 ° C)
A: distillate specific gravity, distillate Density (15 ° C.) / pure water Density (15 ° C.), thus, A is a value obtained by converting the specific gravity of the alcohol concentration in the distillate First, the extent to which the sample (volume V ₁₎ leaves the alcohol Is distilled with steam or heated with steam to obtain a _{sample containing no alcohol (volume V 2} , density ρ _2).

Next, the extract concentration E of the sample containing no alcohol is calculated based on the above equation (1).

E = (S ₀ −A ₀ ) × 260 + 0.21 ・ ・ ・ (1 ´)
S ₀ : Specific gravity of sample containing no alcohol (15/4 ° C) = ρ ₃ / ρ ₀
A ₀ : Specific gravity of pure water (15/15 ℃) = 1
ρ ₃ = {(ρ ₂ -ρ ₁₀ ) × V ₂ / V ₁ } + ρ ₁₀
ρ ₀ : Pure water density at 4 ° C = 0.99997, ρ ₁₀ : Pure water density at 15 ° C = 0.99910
ρ ₃ : The density of the sample containing no alcohol at 15 ° C. On the other hand, when the extract concentration E is obtained, the formula (1) can be converted into the formula (2) to obtain the alcohol concentration A.

A = S- {(E-0.21) / 260} ・ ・ ・ (2)
E: Value obtained by the calculation of the above formula (1')

In the above, since it is not necessary to obtain a distillate of the sample as in the conventional case, steam distillation to expel all alcohol or heat treatment with steam is sufficient. In addition, it is possible to correct an error due to the extract content contained in the alcohol concentration of the non-distilled sample from the extract content of the sample containing no alcohol content.

First, the National Tax Agency Prescribed Analytical Method 3-7 presents a method for calculating the extract concentration in the above distillation method.

E = (SA) x 260 + 0.21 ... (1)
E: Extract content (degree)
S: Sample specific gravity, sample density (15 ° C) / pure water density (4 ° C)
A: Distillate specific gravity, sample density (15 ° C) / pure water density (15 ° C), therefore, A is the value obtained by converting the alcohol concentration of the distillate into specific gravity. become that way.

A = S- {(E-0.21) / 260} ・ ・ ・ (2)
Therefore, the volume V ₁ of the sample at 15 ° C. _{is obtained, and the density ρ 1} of the sample at 15 ° C. is obtained. This is steam-distilled or steam-heated to obtain a sample containing no alcohol, and the volume V ₂ and the density ρ ₂ at 15 ° C. are obtained. Here, the sample containing no alcohol means a liquid after the alcohol content is completely removed and a non-volatile solution remaining therein. Further, the volume V ₁ of the sample is sufficient because the sample obtained from the sample containing no alcohol can be analyzed in a small amount. Further, since steam distillation or steam heating is used, the capacity V ₂ of the sample containing no alcohol is larger than the _{sample capacity V 1.}

Here, in the present invention, the extract concentration E is obtained by using the sample from which the alcohol content has been removed.

The sample volume V ₁ is obtained from the density ρ ₁ and the weight M _{1 of the sample, and the volume V 2} of the sample containing no alcohol (hereinafter referred to as the residual sample) is obtained from the density ρ ₂ and the weight M _{2 of the remaining sample.} It will be. Further, the densities ρ ₁ and ρ ₂ can be obtained by a vibration type densitometer.

Here, assuming that the residual sample is in a state where the extract is dissolved in pure water, _{and considering the density of pure water at 15 ° C. (ρ 10} = 0.99910), the density ρ _{3 of the} residual sample is as follows (ρ 3). 3) Equation.

ρ ₃ = {(ρ ₂ -ρ ₁₀ ) × V ₂ / V ₁ } ＋ ρ ₁₀・ ・ ・ (3)
From the density ρ ₃ of the remaining sample, the specific gravity S ₀ (S in the equations (1) and (2)) of the remaining sample can be obtained. That is,
S ₀ = ρ ₃ / ρ ₀
(Ρ ₀ = 0.99997 is the density of pure water at 4 ° C)
Further, the alcohol concentration of the remaining sample (specific gravity with respect to pure water at 15 ° C.) A ₀ (A in the formulas (1) and (2)) can be assumed here as pure water for the following reasons.
A ₀ = ρ ₁₀ / ρ ₁₀ = 1
Is. That is, the alcohol specific gravity A of the distillate of the above formula (1) is here the alcohol specific gravity of the distillate when the residual sample is distilled, but since the residual sample is a liquid from which the alcohol content has already been removed, the distillate thereof. The liquid can be assumed to be pure water.

Therefore, from the formula (1), the extract concentration (specific gravity) E of the sample is from the above formula (1').
E = {(ρ ₃ / ρ ₀ ) -1.00000} × 260 + 0.21 ・ ・ ・ (4)
Will be.

Since the extract concentration E is obtained, the alcohol concentration of the sample can be calculated based on the formula (2).

The sample specific gravity S in the formula (2) is the ratio (ρ ₁ / ρ ₀ ) of the sample density at 15 ° C. and the pure water density at 4 ° C., and the sample specific gravity S and the extract content concentration (specific gravity) E. Is substituted into Eq. (2) to obtain the alcohol specific density A of the sample. When the density corresponding to this alcohol specific gravity is converted into a concentration (predetermined analysis method, Table 2), the desired alcohol concentration can be obtained.

Based on the above, a specific example of the alcohol concentration corrected for the error due to the extract content is as follows.

(A) Calculation of the extract concentration of the sample (residual sample) that does not contain alcohol
Volume of distilled sample (measured value): 10.067 ml (V)₁)
Volume of residual sample after distillation (measured value): 63.711 ml (V)₂)
Density of residual sample after distillation (measured value): 0.99917 g / cm³: (Ρ₂)
Density of pure water (literature value): 0.99910g / cm³: (Ρ_Ten)
When formula (3) is calculated based on the above, the density (estimated value) of the sample containing no alcohol is ρ. ₃Can be asked.

ρ ₃ = [(0.99917-0.99910) × (63.711 / 10.067)] +0.99910 = 0.99954
_{Here, if S = S 0} and A = A _{0 of the} formula (1) E = (SA) × 260 + 0.21, the extract concentration E of the sample (residual sample) containing no alcohol is determined.
S ₀ : Specific gravity of the remaining sample (15 ° C / 4 ° C): ρ ₃ / ρ ₀ = 0.99957
A ₀ : Specific gravity of pure water (15 ℃ / 15 ℃): 1.00000 (ρ ₁₀ / ρ ₁₀ )
Since the alcohol concentration of 0 vol% is converted to the specific gravity (15 ° C / 15 ° C), the extract concentration E is
E = (0.99957-1.00000) × 260 + 0.21 = 0.10
Therefore, the extract concentration (estimated value) E of the sample is 0.10.
(b) From the sample specific gravity / extract content and equation (2), the alcohol content is calculated back as follows.

S: Sample specific density (15 ° C / 4 ° C) (calculated value): 0.95547
Sample density (measured at 15 ° C): 0.95544g / cm ³
Pure water density (4 ℃): 0.99997g / cm ³
A = 0.95547-[(0.10-0.21) / 260] = 0.95589
Alcohol specific density (15 ℃ / 15 ℃) (estimated value) A: 0.95589
Alcohol density (estimated value): 0.95589 × ρ ₁₀ = 0.95503g / cm ³
Alcohol concentration (calculated from density): 37.440vol%
Will be.

Table 1 shows the results of comparison between the alcohol concentration of whiskey measured by the method according to the present invention and the measurement by the predetermined method (direct flame method) and SDK method which have been conventionally used. Here, the true value of the estimated alcohol concentration of the whiskey to be measured, which is obtained by the procedure described later, is 37.680 V%.

In the direct flame method, a predetermined amount of sample is distilled by direct flame until 70% or more of the sample flows out, water is added to the distillate, and the sample is adjusted to the predetermined amount at 15 ° C. to obtain a specific density at 15 ° C. It is a method of obtaining and converting the specific gravity into an alcohol concentration using the above table.

The SDK method uses the above table when the density of the sample at 15 ° C is ρ ₁₅ and the weight is m ₁₅ , and the distillate obtained by steam distilling the sample has a density of ρ ₂₀ and a weight of m _{20. When the alcohol concentration A is obtained from the density ρ 20 of the} distillate using the sample, the alcohol concentration X of the sample is X = A · m ₂₀ · ρ ₁₅ / (m ₁₅ · ρ ₂₀ ). It is a method that can be measured without management and measurement.

Although the difference from the estimated true value was obtained from the average value of three times in each measurement method, it can be understood that the result obtained by the method according to the present invention has the smallest error.

The estimated true value is obtained as follows.

Table 2 shows the measurement of the ethanol standard solution (label display concentration 40.640v%) whose true value is known by the direct flame method and the SDK method. Here, the average value -0.056v% of the difference from the true value for both methods (direct fire method-0.065v%, SDK method-0.47v%) is obtained. On the other hand, the average value of whiskey measurement results by both methods is 37.623 v%, and when the above 0.056 v% is added to this value, an estimated true value of 37.680 v% is obtained.

The final stage (whiskey estimated value) in Table 2 is a value obtained by adding 0.056 v% to each of the average values of 37.637 v% and 37.610 v% of the measured concentrations of the direct flame method and the SKD method, respectively. ..

Industrial application field

As described above, the present invention can obtain an alcohol concentration in which the error of the alcohol concentration due to the extract is corrected without going through the distillation step for obtaining the distillate. In comparison, the task of finding the alcohol concentration of alcoholic beverages more accurately and easily becomes extremely easy.

Claims (1)

The step of obtaining a sample (volume V2, density ρ2) containing no alcohol by steam distillation or heating the sample (volume V1) to the extent that alcohol is removed, and
A step of calculating the specific density E of the extract content of the sample containing no alcohol based on the formula (1), and
E = (S0-A0) × 260 + 0.21 ... (1)
S0: Specific gravity of sample containing no alcohol (15/4 ° C) = ρ3 / 0.99997,
A0: Specific gravity of distillate containing no alcohol (15/15 ℃) = 1,
ρ3 = {(ρ2-ρ10) × V2 / V1} + ρ10,
ρ10: Pure water density (15 ° C),
ρ3: Density of the extract of the sample containing no alcohol,
The step of calculating the alcohol concentration A based on the formula (2) and
A = S- {(E-0.21) / 260} ... (2)
S: The sample specific gravity is sample density (15 ° C) / pure water density (4 ° C),
E: The value obtained by the calculation of the above equation (1),
An alcohol concentration measuring method characterized by being provided with.