National Research Institute of Brewing
May 2023

The origin of the aroma ofHonkaku shochu and Awamori
National research institute of brewing

Flavor wheel of Honkaku shochu・Awamori

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National Research Institute of Brewing
May 2023

Code Term
Compound
CAS Number, Molecular Weight

Pictureimage

Structural formula

Detection threshold:●● mg/L

Associated term(s):●●Characteristics:
Origin:111 Isoamyl acetate
Isoamyl acetate
CAS 123-92-2、MW 130.2

O
Detection threshold:
240 mg/L

O
Associated term(s):Banana

Characteristics:This ester gives some fruit its distinctive
aroma, often reminiscent of banana.
Origin:Mainly produced by yeast during fermentation. Insake, yeast with an enhanced capacity to produce isoamyl
alcohol will generate high levels of this compound.

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National Research Institute of Brewing
May 2023

112 Ethyl caproate
Ethyl caproate
CAS 123-66-0、MW 144.2

O
Detection threshold:
15 mg/LO

Associated term(s):Apple
Characteristics:This ester produces a sweet aroma
reminiscent of apples.
Origin: Mainly produced by yeast during fermentation. Highly
productive yeasts also exist. This compound is alsoabundant in sake-kasu (sake lees) shochu made from ginjo
lees.

113 Ethyl isobutyrate
Ethyl isobutyrate
CAS 97-62-1、MW 116.2

OO

Detection threshold:3.9 mg/L

Associated term(s):Pineapple
Characteristics: A sweet aroma reminiscent of fruit andpineapple
Origin: Mainly produced by yeast during fermentation. In
sake, it is known to increase during storage.

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National Research Institute of Brewing
May 2023

120 Ethyl acetate
Ethyl acetate
CAS 141-78-6、MW 88.1

ODetection threshold:29000 mg/L

O

Associated term(s):Ester, Ethyl acetate
Characteristics: (If in excess) An aroma like that of nailpolish remover or glue or overripe melon
Origin: Mainly produced by yeast during fermentation. It iswidely included not only in honkaku shochu and awamori,but also in other distilled spirits.

210 Rose oxide
Rose oxide
CAS 16409-43-1、MW 154.3

O
Detection threshold:0.058 mg/L

Associated term(s):Flowery
Characteristics: Sweet and gorgeous floral aroma
Origin: In the production of sweet potato shochu, citronellol
in the mash is converted by an acid-catalyzed chemical
conversion action in the fermentation process, and theconversion is accelerated in the distillation process.

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May 2023

211 β-Phenetyl alcohol
β-Phenetyl alcohol
CAS 60-12-8、MW 122.2

Detection threshold:
18000 mg/L

OH

Associated term(s):Rose
Characteristics: Pleasant floral aroma like that of roses
Origin: Produced in association with phenylalanine
metabolism in yeast. It depends on the amino acidcomposition and the total amount of nitrogen source in themash.

212 Linalool
Linalool
CAS 78-70-6、MW 154.3

Detection threshold:6.6 mg/L

HO

Associated term(s):LavenderCharacteristics: Floral aroma of lavender and lily of thevalley
Origin: In the production of sweet potato shochu,
monoterpene glycosides in sweet potatoes are degraded byenzymes in the koji, and then converted to linalool by theacid and heat of distillation.

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May 2023

213 β-Ionone
β-Ionone
CAS 79-77-6、MW 192.3

Detection threshold:1.7 mg/L

O

Associated term(s):Fragrant olive
Characteristics: An aroma reminiscent of violet flowers.
Origin: It is often formed when orange sweet potatoes areused in the production of sweet potato shochu. A
relationship with β-carotene has been suggested.

214 β-Damascenone
β-Damascenone
CAS 23696-85-7、MW 190.3

Detection threshold:
0.0083 mg/L

O

Associated term(s):Honey, Sweet flowery
Characteristics: Aroma of roses and honey or a sweet
aroma like that of black tea and apple compote.
Origin: The characteristic aroma of sweet potato shochu.
Most of the free β-damascenone is formed in the latter halfof the distillation process.

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May 2023

311 Vanillin
Vanillin
CAS 121-33-5、MW 152.2

HOOO

Detection threshold:
230 mg/L

Associated term(s): Vanilla
Characteristics: Sweet aroma characteristic of vanilla, themain flavor component of vanilla bean.
Origin: Imparted to alcoholic beverages by cask storage. The
compound is also produced in kusu (matured awamori) thathas been stored.

312 Sotolon
Sotolon
CAS 28664-35-9、MW 128.1

OOOH

Detection threshold:9.4 mg/L

Associated term(s):Caramel
Characteristics: Sweet notes of caramel, burnt sugar, andmaple syrup.
Origin: It is produced by storing awamori in an earthenware
jar. The compound's involvement in the aroma of kusu has
been suggested.

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May 2023

313 Whiskey lactone
Whiskey lactone
CAS 39212-23-2、MW 156.2

O

Detection threshold:
40 mg/LO

Associated term(s):Coconut
Characteristics: A sweet aroma reminiscent of coconut.
Origin: Imparted to alcoholic beverages by barrel storage.
This compound is the characteristic aroma of oak barrel
storage.

411 2-Furanmethanthiol
2-Furanmethanthiol
CAS 98-02-2、MW 114.2

Detection threshold:0.0016 mg/L

Associated term(s):Coffee, Roast
Characteristics: A savory aroma reminiscent of coffee or apungent burnt aroma.
Origin: It is generally produced in the heating process offoods. The compound may also transfer from roasted raw
materials. It is considered to contribute to thecharacteristics of barley shochu distilled at atmosphericpressure.

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May 2023

412 2-Ethyl-3,5-dimethylpyrazine
2-Ethyl-3,5-dimethylpyrazine
CAS 13925-07-0、MW 136.2

NDetection threshold:5 mg/LN

Associated term(s):Nuts, Roast
Characteristics: Nutty, cocoa-like aroma.
Origin: It is generally produced in the heating process offoods. The compound is relatively abundant in barleyshochu and brown sugar shochu.

420 Furfural
Furfural
CAS 98-01-1、MW 96.1

Detection threshold:15000 mg/L

Associated term(s):Smoky
Characteristics: Smoky and sweet aroma.
Origin: Formed when sugars are heated under low pH
conditions by citric acid during distillation. The compound isabundant in the latter fraction of the distilled spirit.

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May 2023

430 4-Vinylguaiacol
4-Vinylguaiacol（4-VG）
CAS 7786-61-0 、MW 150.2

OH
Detection threshold:
57 mg/LO

Associated term(s):Smoked
Characteristics: A thick aroma, reminiscent of smoked foodOrigin: It is produced by the release and decarboxylation of
ferulic acid derived from raw materials by the enzyme ofshochu koji fungi. The compound is also produced byheating in the distillation process.

440 Guaiacol
GuaiacolCAS 90-05-1 、MW 124.1

OHO

Detection threshold:
18 mg/L

Associated term(s):Medicinal
Characteristics: Chemical-like aroma characteristic ofphenolic compounds or an aroma reminiscent of disinfectant.
Origin: It is known to exist abundantly in sweet potatoshochu. In whisky, it is contained mainly in the peat smoke.

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May 2023

510 S-Methyl thioacetate
S-Methyl thioacetate
CAS 1534-08-3、MW 90.2

O
Detection threshold:
50 mg/LS
Associated term(s):Sulfide

Characteristics: A sulfuric compound aroma reminiscent ofeggs.
Origin: In beer, it is known to be produced by yeast frommethanethiol, also a sulfur compound, and methionine, anamino acid.

511 Dimethyl trisulfide
Dimethyl trisulfide（DMTS）
CAS 3658-80-8、MW 126.3

SS

Detection threshold:0.037 mg/L

S

Associated term(s):Japanese pickles
Characteristics: An aroma reminiscent of Japanese pickled
vegetables such as takuan; a sulfur compound aroma.
Origin: It is thought that sulfur-containing amino acids in themash are involved; the compound is relatively abundant inawamori.

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May 2023

610 Acetic acidAcetic acid
CAS 64-19-7、MW 60.1
vinegarO

Detection threshold:39000 mg/L

OH

Associated term(s):Acetic smell
Characteristics: Stimulating aroma of vinegar or an aceticsmell.
Origin: Mainly produced by yeast. The amount produced
increases particularly in the production of brown sugar
shochu due to the high temperature and high sugarconcentration.

621 Butyric acid
Butyric acid
CAS 107-92-6、MW 88.1

O
Detection threshold:1300 mg/L

OH
Associated term(s):CheeseCharacteristics: Cheese or buttery aroma.
Origin: Formed when the mash is contaminated bymicroorganisms.

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May 2023

622 Diacetyl
Diacetyl
CAS 431-03-8、MW 86.1

O
Detection threshold:5.6 mg/L

O
Associated term(s):Yogurt

Characteristics: Yogurt-like aroma or sweet aroma
Origin: When purple sweet potatoes are used, the compoundis thought to accumulate as a result of anthocyanins
inhibiting the yeast's diacetyl metabolism. The compound isalso produced through contamination by lactic acid bacteria,etc.

710 Hexanal
Hexanal
CAS 66-25-1、MW 100.2

Detection threshold:
20 mg/LO
Associated term(s):Herbal

Characteristics: Green scent of grass and soybeans. Whenin excess, it is perceived as an oxidized oil odor.
Origin: Produced by the breakdown of long-chain fatty acids
such as linoleic acid.

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May 2023

711 Acetaldehyde
Acetaldehyde
CAS 75-07-0、MW 44.1

O

Detection threshold:9000 mg/L

Associated term(s):Aldehyde, Herbal
Characteristics: A light aroma reminiscent of wood, grass,and green apple.
Origin: There are two routes: where it is produced by yeast
from amino acids, and where it is produced by heating anddecomposing amino acids during distillation; the compound
is abundant in first pours from the outlet.

721 Isovaleraldehyde
Isovaleraldehyde
CAS 590-86-3、MW 86.1

Detection threshold:3.6 mg/L

O

Associated term(s):Stufly smell, Solvent
Characteristics: Stimulating aroma, sometimes described assavory.
Origin: Formed from leucine by yeast metabolism during
fermentation. The compound is thought to be produced by
Strecker degradation in heating during distillation.

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May 2023

722 Isoamyl alcohol
Isoamyl alcohol
CAS 123-51-3、MW 88.2

Detection threshold:33000 mg/L

OH

Associated term(s):Ink, Solvent, Alcohol
Characteristics: Aroma like that of higher alcohol or ink.
Origin: Produced in association with leucine metabolism inyeast. It depends on the amino acid composition and thetotal amount of nitrogen source in the mash.

810 Caprylic acid
Caprylic acid
CAS 124-07-2、MW 144.2

ODetection threshold:1500 mg/L

OH

Associated term(s):Oily, Resin
Characteristics: A slightly heavy aroma reminiscent of oil orresin.
Origin: An intermediate in the fatty acid synthesis pathwayof yeast. The more active the yeast growth and the higher
the nitrogen/carbon ratio in the growth environment, thegreater the amount produced.

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May 2023

820 Ethyl laurate
Ethyl laurate
CAS 106-33-2、MW 228.4
ODetection threshold:99 mg/LO

Associated term(s):Soapy, Oily
Characteristics: A slightly heavy scent reminiscent of oil orsoap.
Origin: Formed when lipids derived from raw materials aredegraded by enzymes and compounded with ethanol. Since
it is also produced during maturation, it is also abundant inkusu (matured awamori).

830 1-Octen-3-ol
1-Octen-3-ol
CAS 3391-86-4、MW 128.2

OHDetection threshold:
5.0 mg/L

Associated term(s):Mushroom
Characteristics: An aroma reminiscent of mushrooms suchas matsutake; also known as matsutakeol.
Origin: It is an ingredient derived from koji, and is mainly
produced by black koji fungus. Therefore, it is especiallyabundant in awamori that uses only rice koji, cultivatedfrom black koji fungus, and water as ingredients.

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May 2023

840 2,4,6-Trichloroanisole
2,4,6-Trichloroanisole（TCA）
CAS 87-40-1、MW 211.5

ClClO

Detection threshold:0.0018 mg/L

Cl

Associated term(s):Moldy
Characteristics: An aroma reminiscent of mold. A substance
responsible for the cork smell of wine.
Origin: Taint. Precursors are generated when chlorine
disinfectants and other chemicals are used on wooden
utensils in manufacturing facilities, and mold converts themto TCA.

Documents Change History
Document name

DateChange Details

112

Ethyl caproate

May 22, 2023

Detection threshold
240mg/L → 15 mg/L

411

2-Furanmethanthiol

May 22, 2023

Origin was added17©2023 NRIB All Rights Reserved.