Claims:We claim,
1. An apparatus for removal of harshness of fresh malt spirit, the apparatus (100) comprises:
a. a reaction vessel (101) to carry the fresh malt spirit;
b. a hot plate (102) on which the reaction vessel (101) is placed;
c. a magnetic stirrer (103) placed into the reaction vessel (101) to
continuously stir the fresh malt spirit;
d. a magnetic stirrer control knob (104) on the exterior of the hot plate (102) to regulate the speed of the magnetic stirrer (103),
e. a temperature control knob (105) on the exterior of the hot plate (102) to regulate the temperature in the reaction vessel (101),
f. a temperature probe (106) placed into the reaction vessel (101) and connected to the temperature display (108) to monitor the temperature,
g. an airtight lid (107) placed on the top position to open and close the reaction vessel (101);
h. a pressure gauge (109) placed on the left side top position of the reaction vessel (101), to regulate the pressure;
i. an oxygen gas regulator (110) to regulate the oxygen gas purging; and
j. an oxygen gas cylinder (111) connected to the reaction vessel (101) for purging oxygen gas into the reaction vessel (101).

2. A method for removal of harshness of fresh malt spirit, the method (200) comprising the steps of:
a. adding fresh malt spirit into a reaction vessel (201);
b. purging the oxygen gas into a reaction vessel to maintain the pressure (202);
c. heating fresh malt spirit slowly with continuous stirring to elevate the temperature (203);
d. maintaining the pressure and temperature as in Step (202) and (203) for a period of one to four weeks; (204) and
e. analyzing the obtained fresh malt spirit for harshness and one or more sensory attributes (205).

2. The method as claimed in claim 2, wherein the oxygen gas purged is in the range between 0.3 to 2.0 kg/cm2.

3. The method as claimed in claim 2, wherein the temperature during heating fresh malt spirit is maintained in the range between 300C to 500C.

4. The method as claimed in claim 2, wherein said harshness of fresh malt spirit is reduced by at least 63% i.e. from 6 to 2 and freshness from 8 to 3.

5. The method as claimed in claim 2, wherein harshness is reduced by oxidation of sulphur compounds in the oxidative environment created by the elevated temperature, oxygen pressure for extended time.

6. The method as claimed in claim 2, wherein sweetness of fresh malt spirit is enhanced by at least 40%.

7. The method as claimed in claim 2, wherein the fruity note of fresh malt spirit is enhanced by at least 40%.

8. The method as claimed in claim 2, wherein the floral note of fresh malt spirit is enhanced by at least 33%.

9. The method as claimed in claim 2, wherein the mellow note of fresh malt spirit is enhanced by at least 67%.
, Description:Preamble to the Description

[0001] 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
[0002] The present invention relates to an apparatus for reduction of harshness from fresh malt spirit by using physico-chemical conditions. The invention also relates to a method of reducing the harshness and improvement of sensorial attributes such as sweet, fruity, floral and mellow notes in the fresh malt spirit using specific physical parameters such as temperature, pressure by oxygen gas and time.
Background of the invention
[0003] 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.[J. R. Piggott, Flavour of Distilled Beverages, Origin and Development, 1983, Ellis Horwood Limited] and the presence of little higher concentration of acetic acid, which contribute to harsh and pungent notes in the malt spirit. The acetic acid is pungent but required during maturation for ester formation. However, the sulphur compounds are not desirable as they impart harshness to the fresh malt spirit and need to be removed.
[0004] The quality of fresh malt spirit is affected by the presence of undesired harshness and the maturation or aging of fresh malt spirit is a complex phenomenon with various chemical reactions occurring simultaneously during the process of aging of the spirit. The maturation or aging of the fresh malt spirit is achieved by storing distilled spirits in barrels or wooden casks for a specific period of time. The goal of maturation or aging is to remove harsh flavors from the fresh malt spirit, while adding distinct flavor characteristics found in the barrel's wood. The process typically requires several months to years to achieve removal of harshness and to improve sensory attributes.
[0005] Due to warm Indian climatic conditions, during the process of removal of harshness during maturation, the cask release good amount of wood extractives along with astringency. This also overpower the goodness of distillery congeners thereby developing very complex malt spirit, which may be taste challenging. Also, the lifetime of wooden cask is reduced drastically due to the higher wood extraction from cask during each cycle of maturation. Reduced ageing in cask in warm Indian climatic condition is preferred to have right amount of wood extractives with retaining goodness of distillery congeners. However, while doing so, the harshness of fresh malt spirit can be perceived in the matured malt spirit.
[0006] The aging process of fresh malt spirit occurs through complex chemical reactions, which are broadly classified into additive reactions, subtractive reactions and interactive reactions. In additive reactions, the wood components are leached into fresh malt spirit, thereby providing desired woody notes. In the interactive reactions, desired fruity notes are developed by slow esterification of ethyl alcohol and fuel oils with acetic acid and higher fatty acids. More importantly, in case of subtractive reactions, the undesired sulphur compounds such as thiophene, 2-methyl thiophene, 2, 5 dimethyl thiophene, S-methyl thioacetate, dimethyl trisulphide, dimethyl disulphide etc. which are responsible for harshness in fresh malt spirits either get trapped in the cask wood or are lost through its pores during maturation of the malt spirit [Clyne et al, International Journal of Food Science and Technology, Vol 28, pp 69-81]. However, this is a very slow process and hence it is essential to accelerate it by rapid elimination of undesired sulphur compounds to reduce the harshness of the fresh malt spirit faster.
[0007] The aging process involves enough amount of cost and time in order to obtain a quality spirit. Further, the process lengthens the production cycle to years and severely limits the production capacity.
[0008] Various methods are available related to the reduction of harshness during the aging process of the spirit.
[0009] The Chinese Patent Application CN201410382654 discloses an aging method of a distilled spirit. The method comprises storage of wine liquid followed by steam introduction and control of the temperature. According to the method, the wine storage temperature is controlled by introducing wine steam, physical reaction and chemical reaction of a wine is accelerated, the aging of the wine is promoted, the storage time is greatly reduced, and the foreign flavor, mud flavor, distilled grain flavor and bitter taste of wine liquid are also removed to ensure that a wine body is soft and pure and is harmonious in taste. The invention discloses only the adjustment of the temperature but not the other physical parameters.
[0010] The Chinese Patent Application CN95221595 relates to a device for ageing white spirit by simultaneously adopting a chemical method and a physical method which comprises an ultrasonic white spirit ageing machine, a releaser hang basket for chemical ageing accelerator and a releaser for chemical ageing accelerator which are arranged on the cylinder wall of the ageing cylinder of the ultrasonic white spirit ageing machine. The aging process of white spirit is accelerated by treating with ultrasound in the ageing cylinder, so the quality and taste of white spirit are improved. The invention discloses only the direct treatment of ultrasound but not any other physical parameters.
[0011] The US Patent Application US10196595B2 discloses devices and method that enable controlled, repeatable and accelerated aging and infusion of alcohol containing beverages. The device comprises newly reaction canisters in a computer-controlled environment of valves, pumps, interconnecting plumbing, sensors and mixing and dispersing manifolds. The infusing materials include traditional aging or infusing materials such as oaks traditionally used to make barrels for aging and infusion as well as other woods and a variety of non-wood infusion materials such as citrus, beans and seeds. The combination of controls, sensors and computer interface allows for repeatable preparation of aged or infused drinks and for development of new aged or infused drinks.
[0012] The US Patent Application US6344226B1 discloses a method of maturation of spirit by adding a food grade solvent such as ethyl acetate to the oak aged alcoholic product and mixing the two liquids. The resulting mixture is allowed to separate into two layers, a first layer and a second layer. The first layer, including the food grade solvent, flavors, color, alcohol i.e., ethanol and water, is separated from the second layer. The solvent is then removed from the first layer to produce the extract. The extract can be added to a less costly alcoholic beverage, such as grain neutral spirits or sugar beet spirits to produce a beverage having the taste of a mature oak aged alcoholic beverage. The application also discloses an accelerated whisky maturation method, including combining an alcoholic distillate with toasted oak chips, heating and aerating and oxygenating the resulting mixture to produce an accelerated oak aged alcoholic product. The toasted oak chips are then removed.
[0013] The US Patent Application US20180057780A1 discloses a system and method for accelerating the aging process of the spirits. The application discloses two types of aging methods. The first aging method is to soak selected wood fibers or chips with spirits in situ in presence of carbon dioxide. The second aging method is to process selected wood fibers or chips in carbon dioxide to obtain activated wood fibers or chips. The activated wood fibers or chips are then soaked with spirits. The application also discloses a system for spirit aging, which comprises a carbon dioxide supply device with a pump and a filter, a carbon dioxide performance vessel with a temperature and pressure control element, a mesh cage device for holding wood fibers or chips and a carbon dioxide separation and recycle device. Wood and activated wood are further impregnated with natural flavors, vitamins, minerals, antioxidants and therapeutics in a carbon dioxide environment. The activated wood or impregnated wood is then combined with spirit and soaked in ambient, vacuum, pressure or carbon dioxide environment to obtain an aged and flavor enriched spirit.
[0014] In the above prior arts, it has been observed that no efforts have been seen to reduce the harshness of fresh malt spirit by using physico-chemical methods and the right combination of temperature and pressure in oxygen environment. To our knowledge, the existing methods do not disclose the details of selective removal of sulphur impurities from the spirit that lead to harshness.
[0015] Hence, there is a need for removal of harshness from fresh malt spirit prior to maturation in wooden cask.
Summary of the invention
[0016] The invention relates to an apparatus for reduction of harshness from fresh malt spirit by using physico-chemical conditions. The apparatus comprises a reaction vessel, a hot plate, a magnetic stirrer, a magnetic stirrer control knob, a temperature control knob, a probe, airtight lid, a temperature display, a pressure gauge, an oxygen gas regulator, an oxygen gas cylinder.
[0017] The invention also discloses a simple, rapid and selective method for reduction of harshness from fresh malt spirit by using physico-chemical conditions. The method also discloses the improvement of sensorial attributes such as sweet, fruity, floral and mellow notes in the fresh malt spirit using a specific temperature, pressure and time.
[0018] The harshness of fresh malt spirit is removed by eliminating the sulphur compounds using oxidative reduction reactions and by using the physico-chemical parameters such as temperature, oxygen gas pressure and time.
[0019] The method for reduction of harshness is achieved using a specially-design reaction vessel. The physical parameters of the reaction vessel are maintained at standardized temperature and pressure. After adding fresh malt spirit into the reaction vessel, oxygen gas is purged into the reaction vessel to maintain the pressure in the range between 0.3 to 2.0 kg/cm2. The fresh malt spirit is heated slowly with continuous stirring to elevate the temperature to 300C to 500C and the same oxygen gas pressure and temperature are maintained for a period of 1 to 4 weeks. The physicochemical conditions such as the temperature of reaction, pressure of oxygen gas and time of reaction depends on the quality of fresh malts spirit from harshness standpoint. The best results are obtained at a temperature of 380C, oxygen pressure of 0.5kg/cm2 and time of reaction 2 weeks. After two weeks, the fresh malt spirit is sensorially analyzed for harshness and sensory attributes and compared with untreated fresh malt spirit. The higher exposure of above reaction to fresh malt spirit completely reduces sulphur compounds responsible for harsh notes. However, over-oxidation of ethyl alcohol leads to acetaldehyde and acetal formation in the fresh malt spirit, resulting in oxidative sensory note. Hence, optimum time of exposure is essential.
[0020] The method of physico-chemical treatment of the invention results in reduction of the harshness of the fresh malt spirit by 63% i.e. from 6 to 2 and freshness from 8 to 3. However, due to reduced harshness, other desired sensory attributes are unmasked and increased. For example, the sweetness is increased by 40% i.e. from 3 to 5, fruity note is increased by 40% i.e. from 3 to 5, floral note is increased by 33% i.e. from 4 to 6 and mellow note is increased by 67% i.e. from 2 to 6 in fresh malt spirit.
[0021] The sulphur compounds are generally present at ppb level in fresh malt spirit and are below detection limits as analyzed by Gas Chromatography coupled with Flame Ionization Detector (GC-FID) analysis. Hence, to illustrate the reduction of sulphur compounds by physico-chemical conditions, such sulphur compounds such as thiophene, S-methyl thioacetate, dimethyl di-sulphide, 2-Methyl thiophene, 2,5-Dimethyl thiophene, Dimethyl tri-sulphide are spiked in fresh malt spirit (50ppm each) in quantifying level of GC-FID method are exposed to physico-chemical reaction conditions for 2 weeks at 500C and 1.5kg/cm2 oxygen pressure. The results indicate reduction in sulphur compounds up to 70% in 2 weeks’ time without affecting the essential congeners in fresh malt spirit such as esters, acids and aldehydes. Most of these compounds are completely reduced in four weeks.
[0022] The method involves a unique step of maintaining the physico-chemical parameters such as temperature and oxygen gas pressure with a specified time, which results in reduction of harshness of the fresh malt spirit.

Brief description of the drawings
[0023] 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.
[0024] FIG 1 illustrates an apparatus to treat fresh malt spirit to reduce its harshness.
[0025] FIG 2 illustrates a method of removal of harshness of the fresh malt spirit by using physico-chemical conditions.
[0026] FIG 3 illustrates the effect of the physico-chemical treatment on the sensorial attributes of the fresh malt spirit.
[0027] FIG 4 interprets the results of GC-FID chromatogram of reduction in spiked sulphur compounds by physico-chemical conditions.
[0028] FIG 5 illustrates the reduction in the sulphur compounds by physico-chemical conditions.
Detailed description of the invention
[0029] 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.
[0030] 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.
[0031] The term "Oxidation”, means chemical combination of a substance with oxygen or a reaction in which electron is donated as context requires.
[0032] The term "Congeners”, means the impurities that are produced during fermentation of alcoholic beverages, which are responsible for taste and aroma of the alcohol, as the context requires.
[0033] The term "Fresh malt spirit”, means spirit obtained by mashing of malt followed by lautering, fermentation and distillery before maturation in contact with wood. It can also be termed as new make spirit in the western world.
[0034] The term "Gas chromatography”, means chromatography employing a gas as a mobile phase, as the context requires.
[0035] The term "Flame Ionization Detector”, means detection system coupled to Gas Chromatography that measures the concentration of organic compounds in a gas stream, as the context requires.
[0036] 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 the context requires.
[0037] The invention discloses an apparatus for reduction of harshness from fresh malt spirit by using physico-chemical conditions. The invention also relates to a method for reduction of harshness from fresh malt spirit by using physico-chemical conditions. The method involves reduction of harshness and sensorial improvement of attributes such as sweet, fruity, floral and mellow notes in fresh malt spirit using a specific temperature, pressure and time.
[0038] The harshness of fresh malt spirit is removed by eliminating the sulphur compounds using oxidative reduction reactions. The sulphur compounds present in the fresh malt spirit are susceptible to oxidation under strong oxidizing conditions. In this invention, the harshness of fresh malt spirit is removed by using the physical parameters such as temperature, oxygen gas pressure and time.
[0039] The invention discloses a simple, rapid and selective method for removal of harshness and improvement of sensorial attributes, which involves treatment of fresh malt spirit with specified temperature, oxygen gas pressure and time. The treated malt spirit is transferred to wooden casks for maturation with relatively reduced time.
[0040] FIG 1 illustrates an apparatus to treat fresh malt spirit to reduce its harshness. The apparatus (100) comprises a reaction vessel (101), a hot plate (102), a magnetic stirrer (103), a magnetic stirrer control knob (104), a temperature control knob (105), a temperature probe (106), air tight lid (107), a temperature display (108), a pressure gauge (109), an oxygen gas regulator (110) and an oxygen gas cylinder (111). The reaction vessel (101) carrying the fresh malt spirit is vertically placed on the hot plate (102). The reaction vessel (101) is equipped with the magnetic stirrer (103) to continuously stir the fresh malt spirit and is enabled with the magnetic stirrer control knob (104) to regulate the speed of the magnetic stirrer (103) for stirring fresh malt spirit and the temperature control knob (105) to adjust to the required temperature. The continuous stirring allows the heat distribution uniformly during heating in the reaction vessel (101). The reaction vessel (101) comprises the airtight lid (107) at its top to open and close the reaction vessel (101), the temperature display (108) placed on the right side top position to display the temperature connected to the temperature probe (106) placed inside the reaction vessel (101), the pressure gauge (109) placed on the left side top position to monitor the pressure inside the reaction vessel (101). The reaction vessel (101) is connected to the oxygen gas cylinder (111) for purging oxygen gas into it and the required pressure is achieved and maintain using the oxygen gas regulator (110).
[0041] FIG 2 illustrates a method of removal of harshness of fresh malt spirit by using physico-chemical conditions. The method (200) starts with step (201) of adding fresh malt spirit into a reaction vessel. The physical parameters of the reaction vessel are maintained at standardized temperature and pressure. At step (202), oxygen gas is purged into the reaction vessel to maintain the pressure in the range between 0.3 kg/cm2 to 2.0 kg/cm2. At step (203), fresh malt spirit is heated slowly with continuous stirring to elevate the temperature to 300C to 500C. At step (204), the pressure and temperature are maintained as in Step (202) and (203) for a period of one to four weeks. Finally, at step (205), fresh malt spirit is analyzed for harshness and sensory attributes and compared with untreated fresh malt spirit.
[0042] FIG 3 illustrates the effect of the physico-chemical treatment on the sensorial attributes of the fresh malt spirit. The sensorial attributes determine the quality, which alters with the age of the fresh malt spirit. The profile of the sensory attributes of the fresh malt spirit by the experienced in-house sensory panel shows improvement after the physico-chemical treatment as shown in Figure 3. The sensory profile as seen in Figure 3 clearly indicates that the method of physico-chemical treatment of the invention results in reduction of harshness by 63% i.e. from 6 to 2 and freshness from 8 to 3. In addition, other sensory attributes such as the sweetness is increased by 40% i.e. from 3 to 5, fruity note is increased by 40% i.e. from 3 to 5, floral note is increased by 33% i.e. from 4 to 6 and mellow note is increased by 67% i.e. from 2 to 6 in fresh malt spirit.
[0043] FIG 4 interprets the results of GC-FID chromatogram of reduction in spiked sulphur compounds by physico-chemical conditions. The sulphur compounds such as thiophene, S-methyl thioacetate, dimethyl di-sulphide, 2-methyl thiophene, 2,5-dimethyl thiophene and dimethyl tri-sulphide are spiked in fresh malt spirit (50ppm each) in quantifying level of GC-FID method and exposed to physico-chemical reaction conditions for 2 weeks at 500C and 1.5kg/cm2 oxygen pressure. The retention time of thiophene is 6.5 min, S-methyl thioacetate is 6.9 min, dimethyl di-sulphide is 7.3 min, 2-methyl thiophene is 7.6 min, 2,5-dimethyl thiophene is 8.6 min and dimethyl tri-sulphide is 11.8 mins. The results indicate that the sulphur compounds are selectively reduced without affecting the other desired distillery congeners such as, esters, fusel alcohols etc.
[0044] FIG 5 illustrates the reduction in the sulphur compounds by physico-chemical conditions. The sulphur compounds such as thiophene, S-methyl thioacetate, dimethyl di-sulphide, 2-methyl thiophene, 2,5-dimethyl thiophene and dimethyl tri-sulphide are reduced up to 70% in two weeks without affecting the essential congeners in fresh malt spirit such as esters, acids and aldehydes. Further, most of sulphur compounds are completely reduced in four weeks as shown in Figure 5.
[0045] Having generally described in 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 reduction of harshness of fresh malt spirit
[0046] A method for removing the harshness of fresh malt spirit comprises adding fresh malt spirit into a reaction vessel. Oxygen gas is purged in the reaction vessel to maintain the pressure in the range 0.3 to 2.0 kg/cm2. The fresh malt spirit is heated slowly with continuous stirring and by gradually increasing the temperature in the range between 30 to 500C. The pressure and temperature in the vessel are maintained in the said range for a period of one to four weeks. The maintenance of the physical parameters as per the method of the invention results in chemical reaction to reduce the harshness of the fresh malt spirit. The harshness of fresh malt spirit is analyzed and compared with untreated fresh malt spirit. Finally, a fresh malt spirit with reduction in harsh notes is obtained.
Example 2: Effect of physico-chemical treatment on other congeners in the fresh malt spirit
[0047] In addition to the reduction of harshness, the physico-chemical treatment of the fresh malt spirit also results in improvements of other sensory attributes thus improving the quality of the fresh malt spirit. The invention discloses the effect of physico-chemical treatment on fresh malt spirit on major congeners such as esters, higher alcohols, aldehydes and acids present in fresh malt spirit. The effect of physico-chemical treatment of the fresh malt spirit was analyzed using Gas Chromatography (GC) coupled with Flame Ionisation Detector (FID) and Gas Chromatography coupled with Mass Spectrometry (GC-MS). The results indicated that 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. are not affected by physico-chemical treatment. Also, the GC-MS analysis, indicated that the sulphur compounds after the physico-chemical treatment showed partial to complete reduction in their response without any addition peaks. No additional peaks in GC-MS analysis indicated that the sulphur compounds were not transformed to other chemical form during the treatment but completely oxidized into oxide gases thereby escaped from the fresh malt spirit.
[0048] Acetaldehyde level was slightly increased during the physico-chemical treatment due to slow oxidation of ethyl alcohol, which is a major component of the fresh malt spirit. However, the non-significant increase in acetaldehyde level did not impart any sensorial change in the fresh malt spirit. Further, the physico-chemical treatment did not alter the levels of furfural and acetal.
[0049] Similarly, the physico-chemical treatment did not alter the levels of acids such as acetic acid, butyric acid, caproic acid etc. as analyzed by GC-FID.
[0050] The sulphur compounds present in the fresh malt spirit are at ppb levels and are beyond the detection limit as analyzed by Gas Chromatography-Flame Ionization Detector and Gas Chromatography Mass Spectrometry. The absence of sulphur compounds is attributed to the oxidation reaction induced by the physico-chemical treatment.
[0051] The physico-chemical treatment with an optimum temperature and the oxygen gas pressure results in oxidation of the sulphur compounds without affecting the major congeners of the fresh malt spirit. This is evident by the absence of sulphur compounds during GC analysis.
[0052] The invention relates to an apparatus and a method for reduction of harshness from fresh malt spirit to improve sensorial quality. The method is very simple, rapid, which is easy to operate with less time and without disturbing its distillery characters. The method of the invention does not involve use of any external chemical compounds and allows selective removal of sulphur compounds that contributes to the harshness of the spirit through oxidation and reduces overall maturation time with improvement in the quality of matured malt spirit. The method also results in improvement of sweetness, fruity, floral notes and mellow character of fresh malt spirit.
[0053] The method involves the unique step of maintaining the physical parameters such as temperature and oxygen gas pressure with a specified time, which results in reduction of harshness of the fresh malt spirit. The method reduces the overall maturation time of the fresh malt spirit which generally involves several months to years in Indian climatic conditions.