Chemistry of the Aroma and Taste of Sake
[WIP post] Currently integrating BFD 26 and a few other articles. I want to bring in better images and photos that can represent the smells and tastes better. Also representing chemical compounds.
Sake Flavor Wheel
List of Chemical Compounds
This post pulls together a large number of sources to help you learn and evaluate the most common flavors and aromas you’ll experience during your brewing and tasting experience.
For a printable list to take with you, there is a spreadsheet with the same information in a condensed version.
You’ll also find a
100 Fruity/Floral Smell
[131] Ethyl acetate
Japanese: 酢酸エチル
CAS 141-78-6, MW 88.1, bp 77°C
Related Terms: Ethyl vinegar odor, (cemedine odor)
Discrimination threshold (detection): 24mg/L
Content in sake: 20 - 120mg/L
Supplementary information: Solvent-like, Smells like nail polish remover or glue (if excessive).
Origin: Basic ester component, produced by yeast during fermentation. It is also produced by film-forming yeast during the process of kimoto-shubo.
Method of analysis: gas chromatography
Regarding [132] Isoamyl acetate and [133] Ethyl Caproate:
A fruity fragrance derived from esters such as isoamyl acetate (132: code number below) and ethyl caproate (133). These are produced by yeast during fermentation (Figure 2). Of the esters, isoamyl acetate, which has a banana-like aroma, is suppressed in the production of isoamyl acetate under conditions with a large amount of unsaturated fatty acids. About 25 years ago, isoamyl acetate was the main ingredient of ginjo incense. After that, ethyl caproate high-producing yeast was bred by mutating the fatty acid synthesis system, and the current ginjo incense is mainly ethyl caproate, which has apple and pear-like scents.
[Figure 2] Relationship between yeast and metabolism and flavor components
[Table 1] Comparison of aroma components of top-ranked sake from the National New Sake Appraisal
[132] Isoamyl acetate, 3-methyl-1-butyl acetate
Japanese: 酢酸イソアミル
CAS 123-92-2, MW 130.1, bp 142°C
Related Terms: 121 fruit-like banana, 110 ginjo incense
Discrimination threshold (detection): 270μg/L
Content in sake: Trace - 15mg/L
Supplementary information: Esters that make up ginjo incense.
Origin: Produced by yeast during fermentation. The production is suppressed under conditions with a large amount of unsaturated fatty acids (one of the reasons why the length of steaming time and the rice-polishing ratio of ginjo sake are low).
Analysis method: gas chromatography
[133] Ethyl Caproate, Ethyl Hexanoate
Japanese: カプロン酸エチル
CAS 123-66-0, MW 144.1, bp 168°C at 760mm
Related Terms: 122 fruit-like apple, 110 ginjo scent
Discrimination threshold (detection): 120μg/L
Content in sake: Trace - 15mg/L
Supplementary information: Esters that make up ginjo incense.
Origin: Produced by yeast during fermentation. There are also yeasts that have been improved to produce more of this.
Method of analysis: gas chromatography
[140] Alcohol, 150 Flower Scents
It has a sake-like aroma derived from higher alcohols such as isoamyl alcohol (142) and β-phenethyl alcohol (151). These are produced by yeast during fermentation. Isoamyl alcohol is involved in the metabolism of leucine, and β-phenethyl alcohol is involved in the metabolism of phenylalanine. In terms of fermentation conditions, high-grade alcohol is produced when the rice-polishing ratio is high and the fermentation temperature is high. For example, junmaishu, which uses white rice with a rice polishing ratio of 70% or more and is fermented at a high temperature, contains more than 200mg/L of isoamyl alcohol, while junmaishu, which is produced under conditions similar to ginjo, contains less than 150mg/L. There are In addition, yeast that produces a large amount of higher alcohols by causing mutations in the related amino acid metabolism system is being bred. If such yeast is used, high-grade alcohol will be high even if ginjo is performed.
[141] Ethyl alcohol, Ethanol
Japanese: エタノール
CAS 64-17-5, MW 46.1, bp 78°C
[Image Diagram]
[Structural formula]
Related Terms: alcohol smell
Discrimination threshold (detection): 10 g/L
Content in sake: 120 – 170 g/L
Supplementary information: main component of alcoholic beverages. It appears as a characteristic when the characteristics of other ingredients are reduced, such as when a large amount of activated carbon is used in sake. It is also related to the stimulus and intensity of taste.
Origin: Produced by yeast during fermentation.
Method of analysis: gas chromatography
[142] Isoamyl alcohol, 3-methyl-1-butanol (Higher Alcohol)
Japanese: 高級アルコール
CAS 123-51-3, MW 88.1, bp 132°C
[Image Diagram]
[Structural formula]
Related Terms: Fusel Oil Smell
Discrimination threshold (detection): 68 mg/L
Content in sake: 70 - 270mg/L
Supplementary information: The base incense of sake, the smell of a whiteboard marker.
Origin: Produced by yeast during fermentation. Related to amino acid metabolism (leucine) in yeast, it is produced in large amounts when the rice polishing ratio is high and the fermentation temperature is high. In addition, there are yeasts that have been improved to produce a large amount of this.
Method of analysis: gas chromatography
[151] Rose, 2(β)-phenylethyl alcohol, 2-Phenyl ethanol (rose)
Japanese: バラ
CAS 60-12-8, MW 122.16, bp 220°C at 750mm
[Structural formula]
Discrimination threshold (detection): 130 mg/L
Content in sake: 75 - 200mg/L
Supplementary information: The base incense of sake, sweet floral scent.
Origin: Produced by yeast during fermentation. Related to amino acid metabolism (phenylalanine) in yeast, it is produced in large amounts when the rice polishing ratio is high and the fermentation temperature is high. Also, there is an improved yeast like him that produces a lot of this.
Method of analysis: Gas Chromatography
200 Wood/Grass Smell
[210] Wood Scent
Japanese: 木香
CAS number, MW molecular weight, bp boiling point °C
[Structural formula]
Related Terms: Cedar barrel scent
Supplementary information: The smell of barrel sake
Origin: Derived from cedar barrels. The main components are sesquiterpene and his sesquiterpene alcohol. The scent of taruzake wood comes from sesquiterpenes extracted from cedar wood. Recently, along with its fragrance, it has been attracting attention for its relaxing effect and antibacterial properties.
Method of analysis: gas chromatography
[230] Aldehydes
Acetaldehyde (231) is a scent associated with wood, grass, and green apples, and is also called woody scent because it resembles woody scent. It is presumed that if alcohol is added when pyruvic acid, an intermediate metabolite of alcoholic fermentation, is high, the physiological metabolic functions of yeast will change and acetaldehyde will increase. Isovaleraldehyde (232) is produced by enzymatic oxidation of isoamyl alcohol in unpasteurized sake and by Strecker decomposition* of leucine after heating. It is the main component of the pungent odor that occurs when unpasteurized sake is stored, and is thought to contribute to the nutty (240) aroma of long-term aged sake.
[231] Acetaldehyde, Ethanal
Japanese: アセトアルデヒド
CAS 75-07-0, MW 44.0, bp 20°C
[Image Diagram]
[Structural formula]
Related Terms: Woody Scent, Cut Grass, Green apples
Discrimination threshold (detection): 11 mg/L
Content in sake: 110mg/L
Supplementary information: A light scent reminiscent of wood, cut grass and green apples.
Origin: Addition of alcohol when pyruvic acid, an intermediate metabolite of alcoholic fermentation, is high, increases acetaldehyde.
Method of analysis: enzymatic method, gas chromatography
[232] Isovaleraldehyde, 3-methyl-1-butanal, 3-methylbutyraldehyde
Japanese: イソバレルアルデヒド
CAS 590-86-3, MW 86.13, bp 93°C
[Image Diagram]
[Structural formula]
Related Terms: 521 Mouret Scent, 520 Raw Scent
Discrimination threshold (detection): 120 μg/L
Content in sake: 100 – 4100μg/L
Supplementary information: A pungent odor produced when unpasteurized sake is stored at room temperature. It is also a component of old incense
Origin: In unpasteurized sake, it is produced by enzymatic oxidation of isoamyl alcohol. In long-term storage sake, it is produced by Strecker decomposition of leucine.
Method of analysis: gas chromatography
[240] Nutty
Japanese: 木の実様
[Image Diagram]
[Structural formula]
Related Terms: Nuts
Discrimination threshold (detection): Crushed Hazelnuts
Supplementary information: A scent reminiscent of nuts.
Origin: By Maillard reaction during aging. Aldehydes, ketones, pyrazines, and furans have been reported to increase in roasted hazelnuts, and these are components that also increase during the aging process of sake.
[251] 4(p)-vinylguaiacol, 2-methoxy-4-vinylphenol
Japanese: 4-ビニルグアイアコール
CAS 7786-61-0, MW 150.18, bp 224°C
[Image Diagram]
[Structural formula]
Related Terms: 4VG
Discrimination threshold (detection): 52μg/L
Content in sake: 0 – 350μg/L
Supplementary information: Smell reminiscent of smoked and spices found in Junmai sake.
Origin: Ferulic acid contained in the cell wall structure of rice is converted by the enzyme of Aspergillus oryzae, or by conversion by wild yeast or lactic acid bacteria.
Method of analysis: liquid chromatography
300 Grain/Rice Smell
[310] Cereal-like
Japanese: 穀類様
[Image Diagram]
[Structural formula]
Related Terms: White rice odor, rice cake odor
Discrimination threshold (detection): n/a
Supplementary information: Odor reminiscent of cereals
Origin: Unknown. The presence of 2-acetyl-1-pyrroline, hexanal, 4-vinylguaiacol (251), etc. has been reported as the odor of rice.
[320] Rice Nuka (part of rice milled off)
Japanese: 糠
[Image Diagram]
[Structural formula]
Discrimination threshold (detection): Odor reminiscent of rice nuka
Supplementary information: The smell is reminiscent of rice nuka.
Origin: Considered to be thiamine decomposition products and fatty acid decomposition products (hexanal) produced by oxidation of raw rice.
[330] Koji
Japanese: 麹
[Image Diagram]
[Structural formula]
Related Terms: Koji-like
Discrimination threshold (detection):
Supplementary information: The smell is reminiscent of koji.
Origin: In the latter half of koji making, linoleic acid is oxidatively degraded by enzymes of koji mold to produce mushroom-like 1-octen-3-ol and 1-octen-3-one. Methional and phenylacetaldehyde, which are thought to be related to amino acid metabolism, also contribute to the odor of koji.
400 Sweet/Caramel Smell
[410] Sweet Smell
Japanese: 甘臭
[Image Diagram]
[Structural formula]
Related Terms: Yodan Smell
Discrimination threshold (detection): Amazake only made from koji
Supplementary information: A sweet smell reminiscent of starch syrup. It tends to appear in yodan brewed sake and sake that uses aged koji.
Origin: Unknown
[420] Sotolon, 4,5-dimethyl-3-hydroxy-2(5H)-furanone
Japanese: カラメル様
CAS 28664-35-9, MW 128.13, bp 184°C at 760mm
[Image Diagram]
[Structural formula]
Related Terms: 421 honey, 422 dried fruit, 423 molasses, 424 soy sauce
Discrimination threshold (detection): 2.3μg/L
Content in sake: 0 – 140μg/L
Supplementary information: A sweet smell produced when sake is stored. component of old incense.
Origin: Condensation of α-ketobutyric acid and acetaldehyde resulting from the decomposition of threonine, or by Maillard reaction.
Method of analysis: gas chromatography
[421] Honey
Japanese: 蜂蜜
[Image Diagram]
[Structural formula]
Discrimination threshold (detection): Add 5g/100mL astragalus honey
Supplementary information: Smell reminiscent of honey.
Origin: There are reports that sotolon (420), isovaleraldehyde (232), and methional contribute to the aroma of honey, and it is thought that this is due to the balance of these components in sake.
[422] Dried Fruit
Japanese: ドライフルーツ
[Image Diagram]
[Structural formula]
Related Terms: Dried Fruit
Discrimination threshold (detection): Add 2mL/100mL of prune juice
Supplementary information: The scent is reminiscent of dried fruits such as prunes and raisins.
Origin: It is mainly derived from Sotron (420), but it is thought to be due to the balance of ingredients, including acetic acid (831).
[423] Molasses
Japanese: 糖蜜
[Image Diagram]
Discrimination threshold (detection): Add 1g/100mL brown sugar
Supplementary information: The smell is reminiscent of molasses and brown sugar.
Origin: Primarily from Sotron (420).
[424] Soy Sauce (Shōyu)
Japanese: 醤油
[Image Diagram]
Discrimination threshold (detection): Add 1mL/100mL soy sauce
Supplementary information: The smell is reminiscent of soy sauce. The main aromatic component of soy sauce is HEMF, which has a similar structure to sotolon and has a sweet aroma.
Origin: Presumably because they contain common components such as Maillard reaction products of amino acids and sugars.
500 Old/Aging Smell
[510] Old Smell / Scent / Incense
Japanese: 老香 （ひねか）
Sotolon: a lactone and an extremely powerful aroma compound, with the typical smell of fenugreek or curry at high concentrations and maple syrup, caramel, or burnt sugar at lower concentrations
Furan: a colorless, volatile liquid used in some chemical manufacturing industries.
[510 table 2] Changes in flavor associated with storage of Pasteurized sake
Discrimination threshold (detection): Sake is stored at 45°C for 4 weeks
Supplementary information: The oxidized and deteriorated smell that occurs during the storage and distribution process of sake. When sake is stored at high temperature or for a long period of time, an odor called old incense (510) is noted. Old incense is a mixture of various compounds generated by the Maillard reaction and other factors, and the term old incense does not mean the same smell. Another way to describe stale incense is as a mixture of aldehyde (230), nutty (240), spice-like (250), caramel-like (420) and polysulfide (624) characteristics. 510 Table 2 shows changes in flavor associated with storage of pasteurized sake.
Origin: Decomposition of amino acids and related metabolites in sake. The main components are isovaleraldehyde (232) and polysulfide (624). Old incense is affected by the production method, storage and control temperature, which increases the amount of amino acids. Additional information points to DMTS
[520] Unpasteurized Old Smell
Japanese: 生老香
[Image Diagram]
Discrimination threshold (detection): Store namazake at 30°C for 4 weeks
Supplementary information: The oxidized and degraded smell that occurs during the storage and distribution process of unpasteurized sake. Raw incense is the smell that occurs when unpasteurized sake is left unpasteurized for a long period of time. Shoro incense is mainly derived from various compounds produced by enzymatic reactions, and is a mixture of characteristics such as isovaleraldehyde (232), koji (330), and polysulfides (624). Isovaleraldehyde in unpasteurized sake is produced when isoamyl alcohol is oxidized by enzymes derived from koji. 520 Table 3 shows changes in flavor associated with storage of unpasteurized sake.
Origin: The main component is isovaleraldehyde (232), but it also contains properties such as koji (330) and polysulfide (624). More information I haven’t translated.
[530] Sunlight Smell
Japanese: 日光臭（にっこうしゅう）
[Image Diagram]
Related Terms: Barnyard, Animal Smell, Charred Odor
Discrimination threshold (detection): Put sake in a transparent bottle and expose it to sunlight for 3 days.
Supplementary information: When sake packed in blue or transparent bottles is exposed to direct sunlight, the degree of coloring increases and an odor develops. When sake is exposed to sunlight (ultraviolet rays), it becomes colored and has an unpleasant odor of sunlight. The sunlight odor of sake is thought to be due to his 3-methylindole (530 Table 4) from the decomposition of tryptophan, mercaptan (622) from the decomposition of methionine, and others. In order to prevent the quality from being affected by ultraviolet rays, it is desirable to use dark colored bottles such as brown bottles, and by using activated charcoal, tryptophan and kynurenic acid acting as a photosensitizer can be reduced, which stabilizes the quality.
Origin: 3-methyl-indole by decomposition of tryptophan, mercaptan (622) by decomposition of methionine, etc.
600 Sulfur-like Smell
[610] Yeast Like
Japanese: 酵母様
[Image Diagram]
[Structural formula]
Related Terms: Ori (sake sediment) scent
Discrimination threshold (detection): Live Yeast
Supplementary information: Smell of yeast and sake sediment. When the yeast is fresh, it smells hydrogen sulfide (621), but when the yeast autolyzes, it smells juicey and polysulfide (624) due to the decomposition of thiamine.
Origin: Yeast
[620] The Sulfide Group
[Figure 5] (1,2-Dihydroxy-5-(methylsulfi nyl)pentane-3-one)
The sulfide-like group includes hydrogen sulfide (621), mercaptans (622), DMS (623) and polysulfides (624). Dimethyltrisulfide (DMTS), a reference standard for polysulfides, was confirmed to be present above the threshold in stored sake by Isogai et al. DMTS has an extremely low detection threshold of 0.18 μg/L and has an unpleasant odor similar to takuan pickles. DMTS is thought to arise from precursors derived from methionine metabolism (Fig. 5), and research is currently being conducted including the behavior of precursors in mash.
[621] Hydrogen Sulfide
Japanese: 硫化水素
CAS 7783-06-4 , MW 34.1, bp -61°C
[Image Diagram]
[Structural formula]
Related Terms: Sulfur Scent
Discrimination threshold (detection): 31μg/L
Supplementary information: Boiled eggs, the smell of hot springs. It can be felt in moromi and freshly pasteurized sake, but hardly in commercially available products.
Origin: Produced during fermentation by metabolism of sulfur-containing amino acids in yeast (promedium moromi) or decomposition of cysteine and cystine by heat.
Method of analysis: gas chromatography
[622] Ethyl mercaptan, Ethanethiol, Methyl mercaptan, Methanethiol
Japanese: メルカプタン
CAS 74-08-1, MW 62.1, bp 35°C (ethyl mercaptan, ethanethiol)
CAS 74-93-1, MW 48.1, bp 6°C (methyl mercaptan, methanethiol)
[Image Diagram]
[Structural formula]
Related Terms: Bottle Scent, “Sitting in the Sun” Smell
Discrimination threshold (detection): 0.41μg/L
Content in sake: 0 – 2 μg/L (methyl mercaptan)
Supplementary information: Smell of onions and gas. Sewer-like, Drains
Origin: Decomposition of methionine by heat, light, etc. The standard sample is ethyl mercaptan, but methyl mercaptan is predominant in sake.
[623] Methyl sulfide, Dimethyl sulfide
DMS
CAS 75-18-3, MW 62.14, bp 38°C
[Image Diagram]
[Structural formula]
Related Terms: Smell of Old Rice
Discrimination threshold (detection): 6.7μg/L
Content in sake: 0- 44μg/L
Supplementary information: Cooked corn, cooked vegetables, Smells reminiscent of green seaweed and corn soup found in sake made with old rice.
Origin: Decomposition of proteins containing S-methylmethionine sulfonium produced by fumigating old rice with ethyl bromide.
Method of analysis: gas chromatography
[624] Dimethyl trisulfide (DMTS), Methyl trisulfide
Japanese: ポリスルフィド
CAS 3658-80-8, MW 126.27, bp 165-170°C
[Image Diagram]
[Structural formula]
Related Terms:
Discrimination threshold (detection): 0.18μg/L
Content in sake: 0 –1.1μg/L
Supplementary information: Smells like pickled pickled radish. component of “old scent”.
Origin: Presumed to be derived from substances derived from the metabolism of the sulfur-containing amino acid methionine.
Method of analysis: gas chromatography
700 Stale/Earthy/Paper
[710] Rubber Smell
Japanese: ゴム臭
[Image Diagram]
Related Terms: Smell reminiscent of rubber.
Discrimination threshold (detection): Refined sake soaked overnight with a red rubber stopper
Origin: Rarely due to rubber products, sulfide-like (620) odor produced by decomposition of sulfur-containing amino acids is thought to be the main odor.
[720] Cork Taint, Musty Smell (2,4,6-trichloroanisole (TCA))
Japanese: カビ臭
CAS 87-40-1, MW 211.47, bp 132°C at 28mm
[Image Diagram]
[Structural formula]
Related Terms:
Discrimination threshold (detection): 0.75ng/L
Content in sake: 0 – 280ng/L
Supplementary information: A musty odor identical to that of wine corks. This is especially a problem with sake such as ginjo sake, which uses a small amount of activated carbon. The musty odor (720) is mainly derived from 2,4,6-trichloroanisole (TCA), as explained by Mr. Iwata in 10 II, Tips for B, F, D of this magazine. In addition to contamination from the environment, if 2,4,6-trichlorophenol (TCP), a precursor of TCA, is present in wooden utensils used for koji production, koji mold will methylate TCP and produce TCA.
Origin: From wood equipment and utensils during manufacturing processes and storage contaminated with TCA. TCA is produced by decomposition of TCP (precursor) by fungi (including Aspergillus oryzae).
Method of analysis: gas chromatography
[731] Paper Smell
Japanese: 紙臭
[Image Diagram]
Discrimination threshold (detection): Refined sake soaked in filter paper overnight
Supplementary information: Papery odor similar to musty odor (720) but perceived as mouth odor.
Origin: Depending on the filter paper used for filtration.
[740] Resin Smell
Japanese: 樹脂臭
[Image Diagram]
Related Terms: Filter Smell
Discrimination threshold (detection): Polypropylene centrifuge tube
Supplementary information: Smell reminiscent of plastic. It is sometimes called the odor of paper packs, but today normal paper pack products (made of polyethylene) do not have an odor.
Origin: Considered to be based on synthetic resin.
800 Diacetyl/Fatty Acid
[810] Diacetyl, 2,3-Butanedione
Japanese: ジアセチル
CAS 431-03-8, MW 86.09, bp 87-88°C
[Image Diagram]
[Structural formula]
Related Terms: Butter-like, yogurt-like, (morning sickness)
Discrimination threshold (detection): 83μg/L
Content in sake: Trace – 500 μg/L
Supplementary information: Slightly sweet smell like fermented butter and yogurt. Diacetyl is produced not only by contamination with lactic acid bacteria, but also by the decomposition of acetolactate produced by yeast during fermentation.
Origin: Upper tank (separation from yeast) during the period when α-acetolactate is abundant, or contamination with lactic acid bacteria.
Method of analysis: gas chromatography
[820] Fatty Acid, n-Caproic acid, Hexanoic acid
Japanese: 脂肪酸
CAS 142-62-1, MW 116.16, bp 205°C
[Image Diagram]
[Structural formula]
[Figure 6] Relationship between caproic acid and ethyl caproate
Discrimination threshold (detection): 2.3mg/L
Content in sake: 4 - 40mg/L
Supplementary information: An oily/resin-like odor found in some ginjo sake.
Origin: Produced by yeast during fermentation. Ethyl caproate increases when yeast with a mutated fatty acid synthesis system is used, while its precursor, caproic acid, increases. When high ethyl caproate production yeast with a mutated fatty acid synthesis system is used, the amount of caproic acid produced increases, and in some cases, it exceeds 50mg/L. (Fig. 6) Therefore, when ethyl caproate is reduced during pasteurization and storage, the properties of caproic acid become more pronounced. For this reason, it is necessary to pay close attention to the storage and shipping management of ginjo sake.
Method of analysis: gas chromatography
[830] The Sour Group
The sour group includes acetic acid (831), butyric acid (832) and isovaleric acid (833). In addition to contamination with lactic acid bacteria, acetic acid tends to increase when the mash is aerated excessively or when the area of the mash that comes into contact with air is large. It also increases due to chemical reactions during the storage period after heating. Butyric acid is mainly produced by lactic acid contamination, and isovaleric acid is produced by Bacillus subtilis contamination of koji. Cleaning and sterilization are the basics of brewing. While there are some breweries that pay attention to details such as zone management, others seem to be neglecting due to an increase in the number of inexperienced employees. Please follow the procedures thoroughly and check the sanitary conditions.
[831] Acetic Acid
Japanese: 酢酸
CAS 64-19-7, MW 60.05, bp 113°C
[Image Diagram]
[Structural formula]
Discrimination threshold (detection): 37mg/L
Content in sake: 38 - 280mg/L
Supplementary information: Smell of vinegar.
Origin: Produced by yeast during fermentation (easily increased when there is excessive aeration or when the mash has a large contact area with the air), or contamination with lactic acid bacteria, etc.
Method of analysis: enzymatic method, liquid chromatography
[832] n-Butyric acid, Butanoic acid
Japanese: 酪酸
CAS 107-92-6, MW 88.10, bp 164°C
[Image Diagram]
[Structural formula]
Related Terms: persimmon astringency
Discrimination threshold (detection): : 4.3mg/L
Content in sake: unclear
Supplementary information: Gingko, cheese-like smell, putrid, baby vomit
Origin: Contamination with hiochi bacteria or migration from persimmon juice.
Method of analysis: liquid chromatography
[833] Isovaleric acid, 3-methylbutanoic acid
Japanese: イソ吉草酸
CAS 503-74-2, MW 102.1, bp 177°C
[Image Diagram]
[Structural formula]
Discrimination threshold (detection): 0.41mg/L
Supplementary information: Cheesy, old hops, sweaty socks, sweaty smell of natto.
Origin: Bacillus subtilis contamination of koji
Method of analysis: gas chromatography
900 - 1300 acidity/sweet/salty/umami/bitter
[910] Acidity
Supplementary information: Sour, Sourness stands outmalic acid (apple sourness)
[1010] Sweetness
[1110] Saltiness
[1210] Umami
[1310] Bitterness
900 - 1300 Mouthfeel
[1410] Astringency
[1420] Irritating / Undesireable Taste
[1430] Texture
[1440] Stickiness / Cloying
[1450] Aftertaste
[1460] Carbon Dioxide Gas
[1470] Metallic Taste
1500 sweet and spicy
[1510] Sweet and Spicy
1600 Shade / Tint
[1610] Shade / Tint / Color
References:
Already included:
https://www.nrib.go.jp/data/pdf/seikoumisan.pdf
https://kitasangyo.com/p清酒のにおいと その由来についてdf/e-academy/tips-for-bfd/BFD_27.pdf
Additional information not yet included:
https://www.kitasangyo.com/pdf/e-academy/tips-for-bfd/BFD_26.pdf
http://www.jsac.or.jp/~gc/pdf/334/334_05.pdf
https://www.jstage.jst.go.jp/article/jao/38/5/38_5_352/_pdf
https://www.jstage.jst.go.jp/article/kagakutoseibutsu/50/12/50_897/_pdf
