Claims:We claim,
1. A method for eliminating the harshness and pungency of fresh malt spirit, the method comprising the steps of:
a. adding optimum concentration of potassium permanganate (KMnO4) as oxidizing agent to fresh malt spirit (101);
b. incubating the mixture of oxidizing agent and fresh malt spirit (102);
c. filtering the residue produced during the chemical reaction of oxidizing agent with fresh malt spirit (103); and
d. obtaining fresh malt spirit with reduction in pungency and harshness and unmasking desired sensory notes such as (fruity, floral, sweet and grassy) (104).

2. The method as claimed in claim 1, wherein the oxidizing agents are selected from a group comprising potassium permanganate, Potassium dichromate (K2Cr2O7) and Hydrogen peroxide (H2O2).

3. The method as claimed in claim 1, wherein oxidizing agent KMnO4 is used at a concentration of at least 30 ppm in fresh malt spirit.

4. The method as claimed in claim 1, wherein fresh malt spirit and oxidizing agent are incubated for a period of at least 18 hours.

5. The method as claimed in claim 1, wherein precipitate produced during chemical reaction is removed by simple filtration technique using a 10-micron filter.

6. The method as claimed in claim 1, wherein said harshness of fresh malt spirit is reduced by at least 60% and pungency by at least 44%.

7. The method as claimed in claim 1, wherein the method enhances the sweetness of fresh malt spirit by at least 40%.

8. The method as claimed in claim 1, wherein the method enhances the fruity note of fresh malt spirit by at least 140%.

9. The method as claimed in claim 1, wherein the method enhances the floral note of fresh malt spirit by at least 100%.

10. The method as claimed in claim 1, wherein the method enhances the grassy note of fresh malt spirit by at least 180%.
, Description:Preamble to the Description

The following specification particularly describes the invention and the manner in which it is to be performed:
Description of the invention
Technical field of the invention
The present invention relates to a method for elimination of harshness and pungency from fresh malt spirit by using an oxidizing agent thus resulting in sensorial improvement of attributes such as grassy, sweet, fruity and floral notes in the fresh malt spirit.
Background of the invention
Fresh malt spirit contains desired congeners such as acids, aldehydes, furfural, esters, higher alcohols etc. and also various undesired sulphur compounds such as thiophene, 2-methyl thiophene, 2, 5 Dimethyl thiophene, S-methyl thioacetate, dimethyl trisulphide, dimethyl disulphide etc., and the presence of little higher concentration of acetic acid, which contribute to harsh and pungent notes in the malt spirit.
Quality of fresh malt spirit plays an important role in the final quality of matured malt spirit. Usually, it is affected by the presence of undesired harsh and starchy notes. The production of fresh malt spirit involves mashing of malted barley followed by lautering, which is subjected to fermentation by yeast to yield alcohol. The fermented alcohol is separated at average alcoholic strength of 63% (v/v) during two stage pot still distillation. The distillation is carried out in copper pot stills, which absorb maximum undesired sulphur compounds generated from amino acids during fermentation. The resultant malt spirit requires to be stored in an oak cask for maturation for a longer time, which loses its harshness by loss of sulphur compounds during the process to yield mellower, sweet, fruity, woody and more rounded malt spirit.
The maturation of fresh malt spirit is a complex chemical phenomenon with different types of chemical reactions occurring simultaneously during the aging of spirit. Generally, these reactions are broadly classified as additive reactions, subtractive reactions and interactive reactions. In additive reactions, the wood components are leached in the fresh malt spirit, providing desired woody notes. In the interactive reactions, desired fruity notes are developed by slow esterification of ethyl alcohol and fusel oils with acetic acid and higher fatty acids. More importantly, in subtractive reactions, the undesired sulphur compounds such as thiophene, 2-methyl thiophene, 2, 5 dimethyl thiophene, S-methyl thioacetate, dimethyl trisulphide, dimethyl disulphide etc. from fresh malt spirits either get trapped in the cask wood or are lost through its pores during maturation of the malt spirit. However, this is a very slow process and hence makes it essential to accelerate by rapid elimination of undesired sulphur compounds in order to mellow the fresh malt spirit faster. The method of the invention discloses the use of potassium permanganate (KMnO4), which selectively eliminates or significantly reduces sulphur compounds of interest without disturbing other desired chemical congeners in the fresh malt spirit. This helps in reducing harshness of fresh malt spirit due to trace level of sulphur compounds. In the reaction of KMnO4 with fresh malt spirit, small amount of potassium hydroxide (KOH) generated, which reduces the pungency due to its reaction with acetic acid. The reduction in harshness and pungency contributes in unmasking the desired notes fruity, floral and grassy notes in fresh malt spirit.
Various methods exist to purify the spirit by different treatments followed by distillation. The Chinese Patent CN104447197A describes a method of removing impurity by adding KMnO4 during alcohol distillation. The invention describes a method of removing impurity from alcohol by distillation system after pretreatment with KMnO4 and sodium hydroxide. This treatment is carried out at distillation temperature for extra neutral alcohol production by removal of impurities as non-volatile salts and also as a precipitate.
The PCT Application WO2012169868A1 describes a production method of a strong alcoholic beverage. In this method, the impurities are removed from spirit by pretreatment with KMnO4 followed by distillation. The invention discloses a technology to minimize or completely remove the cavitation phenomena in a produced drink. The required composition of solution of ethyl alcohol, water and sugar syrup is prepared. The sealed vessel containing the prepared solution is vacuumed and the solution is slowly mixed at pressure of 10 mm Hg and at temperature of 20°C. Finally, the product in a hermetic state is diverted to the bottling. Additionally, when preparing flavored strong alcoholic drinks such as tequila, liqueur, bitter and alike, after the vacuuming is finished, the solution is saturated with nitrogen by applying gasification.
The Patent Application RU94026331A1 describes the method of refining alcohol. In this method, the alcohol is refined through multi-treatment filter such as sand filter, ion exchange resin and carbon filter. The impurities such as organic acids, esters and aldehydes are removed by these treatments.
The US Application US2188274 describes the method of purification of alcohol. The invention discloses the purification of spirit by multiple treatment process, which includes KMnO4 treatment, caustic treatment at elevated temperature, aeration and finally followed by distillation. The treatment is performed at high dose of KMnO4. However, the impurities removed by this treatment are not identified.

The Patent Application CN106434248A discloses a method of using KMnO4 to reduce the intermediate aldehyde produced during the oxidation of alcohol in wine at higher temp (70 deg C) by using high concentration of KMnO4 for a long time, which facilitates the oxidation of intermediate aldehyde to acid and thereby eliminating the off note of aldehyde from distilled wine and improves the flavor profile of wine. The method involves high dose of KMnO4, high temperature and long time with focus to reduce only aldehydes in wine.

The Patent Application US20180320118A1 discloses a process of mechanical treatment such as inducing shock waves and pressure variations within the cavity, where the beer is passed through. The process involves the steps of circulating the spirits through a cavitation zone within a controlled cavitation reactor and exposing the spirits therein to high energy cavitation induced shockwaves. It is a physical method wherein the actual chemical changes responsible for harshness are not clear.
In the above prior arts, it has been observed that no efforts have been seen to reduce the harshness of fresh malt spirit. However, all the above cited prior arts disclose the methods that are performed on neutral spirit with an aim to remove the impurities present in the spirit. To our knowledge, the existing methods do not disclose the details of selective removal of sulphur impurities from the spirit that lead to harshness. The above cited methods used KMnO4 treatment at higher doses to clean alcohol followed by additional step of distillation to yield neutral alcohol. These methods are not specific for elimination of sulphur compounds from the spirit and will not be applicable to fresh malt spirit, as it has desired distillation congeners at right proportion required during maturation.
Hence, there is a need for a method to selectively remove the sulphur compounds and reduce acetic acid levels that contribute to the harshness and pungency in the fresh malt spirit.
Summary of the invention
The invention discloses a method for the elimination of harshness and pungency of fresh malt spirit by virtue of selective removal of sulphur compounds using oxidative reaction. Different oxidizing agents such as KMnO4, Potassium dichromate (K2Cr2O7) and Hydrogen peroxide (H2O2) are tested for the desired reaction. KMnO4 is effective in selective removal of sulphur compounds. The concentration of KMnO4 used in this reaction is very critical to specifically eliminate sulphur compounds without affecting the other desired distillation congeners. After the treatment, KMnO4 is reduced to MnO2 in the form of a precipitate and is eliminated from the system by simple filtration without leaving any residual effect in fresh malt spirit. Additionally, KMnO4 treatment shifts the pH of the malt from acidic towards neutral side and thereby reducing pungency of fresh malt spirit due to acetic acid.
The method of chemical treatment by means of oxidation using KMnO4 is a simple, quick and cost effective and having no residual effect. The method of the invention results in the reduction of harshness of fresh malt spirit within a day, which generally take months or years for maturation in wooden casks.
The invention provides a method for elimination of harshness and pungency by chemical treatment resulting in improvement of sensorial attributes such as fruity, floral, sweet and grassy notes in fresh malt spirit. The process involves the elimination of harshness of fresh malt spirit by addition of 30ppm of KMnO4, followed by incubation for 18 hours to complete the precipitation of MnO2, which is removed by simple filtration process.
The fresh malt spirit obtained at the end of a chemical reaction is more mellow and sweet as compared to untreated fresh malt spirit, which has starchy, pungent and harsh notes.
Object of the invention
The principal object of the invention is to provide a simple and cost-effective process for the treatment of fresh malt spirit by which the undesirable sulphur compounds are eliminated, which are responsible for providing harshness and pungency to the fresh malt spirit.
It is to be understood that the foregoing general description and the following detail description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Brief description of the drawings
The foregoing and other features of embodiments will become more apparent from the following detailed description of embodiments, when read in conjunction with the accompanying drawings. In the drawings, like reference numerals refer to like elements.
FIG 1 shows a flow chart for a method of removing harshness and pungency in fresh malt spirit.
FIG 2 shows a change in sensory profile of fresh malt spirit treated with oxidizing agent in accordance to one or more embodiment of the invention.
Detailed description of the invention
Reference will now be made in detail to the description of the present subject matter, one or more examples of which are shown in figures. Each embodiment is provided to explain the subject matter and not a limitation. These embodiments are described in sufficient detail to enable a person skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, physical, and other changes may be made within the scope of the embodiments. The following detailed description is, therefore, not be taken as limiting the scope of the invention, but instead the invention is to be defined by the appended claims.
In order to more clearly and concisely describe and point out the subject matter of the claimed invention, the following definitions are provided for specific terms, which are used in the following written description.
The term "Oxidation”, means the chemical combination of a substance with oxygen or a reaction in which electron is donated as context requires.
The term "Oxidizing agent”, means a substance that tends to bring about oxidation by being reduced or gaining electrons, as context requires.
The term "Distillation”, means the process of separating the compounds in a liquid based on their difference in boiling point, as context requires.
The term "Distillation congeners”, means the impurities that are produced during fermentation of alcoholic beverages, which are responsible for taste and aroma of the alcohol, as context requires.
The term "Fresh malt spirit”, means spirit obtained by mashing of malt followed by lautering, fermentation and distillation before maturation in contact with wood.
The term "Gas chromatography”, means chromatography employing a gas as a mobile phase, as context requires.
The term "Flame Ionization Detector”, means detection system coupled to Gas Chromatography that measures the concentration of organic compounds in a gas stream, as context requires.
The term "Gas chromatography Mass Spectrometry”, means mass spectrometric detection system coupled to Gas Chromatography that measures and chemically characterized organic compounds in a gaseous mobile phase, as context requires.
The term "Atomic Absorbance Spectrometry”, means analytical technique that measures inorganic ion concentration, as context requires.
The invention discloses a method for elimination of harshness and pungency with improvement of sensorial attributes such as fruity, floral, sweet and grassy notes of fresh malt spirit by chemical treatment. In the preferred embodiment, KMnO4 is added to the fresh malt spirit at an optimum concentration of 30 ppm and incubated for 18 hours at ambient temperature for completion of the reaction. The undesired sulphur compounds in fresh malt spirit are oxidizing as follows:
Fresh malt Spirit + S - compound + KMnO4 + H2O ? Fresh malt spirit + SO2? + MnO2 ?+ KOH (Representative reaction)
In the invention, different oxidizing agents such as KMnO4, K2Cr2O7, and H2O2 are tested and found to be suitable for carrying out oxidation reaction. However, KMnO4 is found to be the most promising and desirable, while considering various factors such as usability, oxidation potential, health hazard and the by-product of the treatment (MnO2), which is easily removable by simple filtration. In the process, the shift in pH of fresh malt spirit from acidic towards the neutral side by formation of KOH causes reduction in pungency of the malt spirit due to partial neutralization of acetic acid. During the chemical treatment, the sulphur compounds that are responsible for harshness are removed and MnO2 precipitated during the chemical reaction is filtered off through simple filtration using 10-micron filter.
Figure 1 illustrates a flowchart depicting a method for eliminating the harshness of fresh malt spirit in accordance with one or more embodiment of the invention. The method (100) starts with step (101) of adding KMnO4 to the fresh malt spirit at an optimum concentration of 30 ppm. At step (102), fresh malt spirit and KMnO4 are incubated for 18 hours at ambient temperature for completion of the reaction. At step (103), MnO2 precipitate produced during the chemical reaction is removed using simple filtration process using 10-micron filter. At step (104) fresh malt spirit is obtained with reduction of pungency and harsh notes.
Having generally described this invention, a further understanding can be obtained by reference to certain specific examples, which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.
Example 1: Method for removing the harshness of fresh malt spirit
A method for removing the harshness of fresh malt spirit is disclosed in the invention that results in reaction of KMnO4 with sulphur compounds in fresh malt spirit as shown below:
Fresh malt Spirit + S - compound + KMnO4 + H2O ? Fresh malt spirit + SO2? + MnO2 ?+ KOH (Representative reaction)
KMnO4 is added in fresh malt spirit at an optimum concentration of 30 ppm and incubated for 18 hours at ambient temperature for completion of reaction, where KMnO4 is reduced to MnO2 and settles as dark brown precipitate at bottom of the flask and sulphur compounds are oxidized to sulphur dioxide (SO2) and eliminated from the reaction system. MnO2 precipitate produced during the chemical reaction is removed using simple filtration process. Finally, a fresh malt spirit with reduction in pungent and harsh notes is obtained.
Example 2: Effect of oxidation by KMnO4 on congeners in Fresh Malt Spirit
The invention discloses the effect of oxidation by KMnO4 on the major congeners groups such as esters, higher alcohols, aldehydes and acids present in fresh malt spirit, which was carried out using Gas Chromatography coupled with Flame Ionization Detector (GC) and Gas Chromatography coupled with Mass Spectrometry Detector (GC-MS). The results indicated that the GC response of esters such as ethyl acetate, ethyl formate, ethyl caproate, ethyl caprylate, ethyl caprate, ethyl laurate, isoamyl acetate, phenethyl acetate etc. and higher alcohols such as n-propanol, n-butanol, isobutanol, isoamyl alcohol, phenethyl alcohol etc. in fresh malt spirit are unaffected by oxidation reaction of KMnO4 at stoichiometric concentrations.
However, in case of aldehydes, GC analysis showed a slight increase in acetaldehyde levels during KMnO4 reaction due to the oxidation of ethyl alcohol, which is the major component of fresh malt spirit. However, furfural and acetal appeared to be unchanged. Similarly, in the case of higher acids, no visible change is evident for butyric acid, caproic acid etc. The slight increase in the acetaldehyde level did not impart any sensorial change in the fresh malt spirit.
The sulphur compounds are found to be partially or completely oxidized by KMnO4 at the stoichiometric concentrations. This is evident by a reduction in the GC response of sulphur compounds after their treatment with KMnO4. The individual sulphur compounds are oxidized with KMnO4 and checked for their conversion using GC-MS. The analysis showed a reduction in GC-MS response of sulphur compounds but no presence of any other by-products in the chromatographic run indicating that elimination of sulphur compounds from the system in the form of oxide gases such as carbon dioxide (CO2) and sulphur dioxide (SO2).
The dose of KMnO4 used for treating fresh malt spirit is very critical. The lower concentration found to be less effective to bring sensorial change in fresh malt spirit and higher concentration found to produce undesirable profile of fresh malt spirit. It has been reported that the concentration ratio of esters to sulphur compounds increases during the course of maturation, which resulted in appealing sensorial fruity and sweet notes. The concentration of 30ppm in fresh malt spirit is found to be very effective for selective oxidation of undesired sulphur compounds without affecting the ester levels and thereby increasing the concentration ratio of esters to sulphur compounds as observed during natural maturation process. Thus, improving the sensory character of fresh malt spirit by removing harshness. The residual manganese (Mn) level in the treated spirit is checked by Atomic Absorption Spectroscopy (AAS) and found to be 1 ppm, which is much below the recommended Mn level in the drinking water by World Health Organization. The change in sensorial attributes of fresh malt spirit by KMnO4 treatment is profiled by the experienced in-house sensory panel and the outcome is shown in Figure 2. The sensory profile as seen in Figure 2 clearly indicates that KMnO4 treated fresh malt spirit has reduced harshness and pungency level from 6 to 2.3 and 5 to 2.8, respectively. Additionally, the fruity, floral, sweet and grassy notes attributes improved from 2.0 to 4.8, 2.0 to 4.0, 3.0 to 4.2 and 2.0 to 3.6, respectively.
The invention provides a method for elimination of harshness and pungency from fresh malt spirit to improve sensorial quality. The method is very simple, which is easy to operate with less time. There is no residual effect of the compound added and practically no spirit loss during the process. The method of the invention allows selective removal of sulphur compounds from the fresh malt spirit that contributes to the harshness of the spirit and reduces overall maturation time and improve the quality of matured malt spirit. The method also results in improvement of sweetness, fruity, floral notes and grassy character of the fresh malt spirit.