The Storyof SakeFeaturedarticleSake(Seishu) 2（ The Integration of Science and Technology）
1
The beginnings of the science of sake brewing
2
Sake brewing
8
Pressing and ﬁnishing
10
Enjoying sake《Special Topics》

Specially designated sake
Yamadanishiki
The safety of koji mold (Aspergillus oryzae)
Foaming yeast and non-foaming yeastOﬀ ﬂavors in aged sake (hine-ka) versus a matured aroma
The pairing of sake with different foods
Alcohol and the J-curve effect

1
2
4
7
10
11
12

Ginjo -shu has a ﬁ ne f r u it y a roma a nd exqu isite
mouthfeel.Jummai-shu has moderate sweetness and great
palatefulness.These two types of sake signiﬁcantly
changed its stereotyped image.The market share on
shipment basis of ginjo-shu and jummai-ginjo-shu has been
increasing year by year. Japanese term Ginjo literallymeans carefully selected and brewed. So ginjo-shu is theculmination of sake brewing technology, embodying
the craftsmanlike spirit of sake brewers throughout thebrewing processes of sake. Sophisticated brewing
technology through the development of ginjo making
has contributed to the quality improvement of thewhole sake industry.The integration of the traditional
skills of the sake brewers (called toji and kurabito) andcutting-edge sake research by scientists has led to the
production of not only ginjo-shu but also various types
and kinds of deep ﬂavored and high quality sake.
This booklet The Story of Sake 2 introduces a moredetailed and deeper discussion of how sake is made,including the integration of science and technology.
This booklet also introduces the processes that were
not included in The Story of Sake 1, from the step ofpressing the fermentation mash to shipping sake as aﬁnished product. It also provides information about thetypes and storage management of sake.
We hope you will enjoy sake more, after learning
about the features of each type of sake, including thed i f fe r e nt de s i g n at ion s de r i ve d f r om r e s p e ct i ve
ingredients and brewing methods.

NRIB(National
Research Instituteof Brewing)
March 20172

The beginnings of the scienceof sake brewing

Sake manufacturing industry is one of the major time-honored
fermentation industries in Japan.Toward 1887, the modern sakemanufacturing industry established. Simultaneously, the mass
production by private sake companies began in Nada in the Hyogo
Prefecture and Fushimi in the Kyoto Prefecture.
At that time, however, sake brewing relied on the experience andintuition of the sake brewers, and therefore the production process
was unstable, and frequently lead to spoilage of sake.Research anddevelopment, e.g. the isolation of indispensable microorganisms forsake brewing, koji mold and yeast were just beginning. However, it
was still a long time before we attained a full scientiﬁc elucidationof sake brewing.
Besides, by 1899 the liquor tax had become the biggest source ofrevenue for the Japanese government, exceeding even the land tax.
When sake spoiled, the prepaid tax had to be returned, meaning
revenue derived from liquor tax was not stable.
The elucidation and countermeasure against sake spoilage cameto an urgent matter. Academic research and investigations into how
to improve sake brewing technology began as a national project
essential to supporting the basis of national revenue.
With this background, the National Research Institute of Brewing(NRIB) was established within the Ministry of Finance in 1904.

Specially designated sakeSpecial designation is a sake classiﬁcation system that fulﬁlls the "standards for thelabeling of the production method and quality of sake" established by the National Tax
Agency JAPAN. There are eight classes in all.
As well as these designations, there are many diﬀerent kinds of sake with diﬀerent
names. Please refer to our Glossary of Terms on Sake Bottle Labels for details.
rice-polishing ratio percent of rice※4
special designation ingredients ※1※2 (seimai-buai) ※3 for making koji other features

ginjo-shu

rice, rice koji,
distilled alcohol

up to 60%at least 15%

ginjo making, good characteristic
ﬂavor and appearance

daiginjo-shu

rice, rice koji,
distilled alcohol

up to 50%at least 15%

ginjo making, excellent characteristic
ﬂavor and appearance

jummai-shu

rice, rice kojiーat least 15%

good ﬂavor and appearance

jummai-ginjo-shu

rice, rice koji

up to 60%at least 15%

ginjo making, good characteristic
ﬂavor and appearance

jummai-daiginjo-shu rice, rice koji

up to 50%at least 15%

ginjo making, excellent characteristic
ﬂavor and appearance

tokubetsu-jummai-shu

rice, rice koji

up to 60%, or
special process

at least 15%

excellent ﬂavor andappearance

honjozo-shu

rice, rice koji,
distilled alcohol

up to 70％

at least 15%

good ﬂavor and appearance

tokubetsu-honjozo-shu

rice, rice koji,
distilled alcohol

up to 60%, or
special process

at least 15%

excellent ﬂavor andappearance*1. The rice used has to be pass an inspection based on Agricultural Product Inspection
Law indicating a certain level of quality*2. The amount of distilled alcohol usage should not exceed 10% of rice weight*3. The rice-polishing ratio has to be indicated on label.
*4. Deﬁnition of ginjo making: Usually refers to the process of using rice with a low rice-polishingratio and low temperature fermentation to create the characteristic ﬂavor of ginjo-shu

Special designations and their speciﬁcations

01

Sake Brewing

Ricepolishing

Rice forsake brewing

Ricewashingand soaking

The Integration of Scienceand Technology

Rice for sake brewing

Sake is an alcoholic beverage made from rice. Currently,
about 300 varieties of rice are cultivated in Japan. Some
varieties of them are used to brew domestic sakes.Somek i nd s of r ice cla s si ﬁed by t he A g r icu lt u r a l P roductStandards as “brow n r ice for sake brew ing” are also
referred to as “sake-brewing rice.” They have superior
properties that make them the most suitable for being usedas the ingredient for brewing sake.Among the sake-brewing
rice varieties, the most cultivated variety was Yamadanishiki.
In addition to Yamadanishiki, many varieties of sake-brewing
rice are grown, throughout Japan.
Rice variety

１ Yamadanishiki

Main harvested site
(prefecture)

Hyogo, Okayama, etc.

Amounts(tons)

２ Gohyakumangoku Niigata, Toyama, etc.
３ Miyamanishiki

Nagano, Akita, etc.

17,561hokkaido

5,710

Gimpu

Akitasakekomachi

akita

Dewasansan
Yamadanishiki
Hattannishiki No. 1

yamagata
niigatanaganohiroshima okayama

hyogo

Table rice (Nipponbare)

Weight per 1,000 grains(this measure is called the
Senryujyu):Approx. 26g

Senryujyu:
Approx. 22g

Cross section

Cross section

Shimpaku: This area looks white because the starch granules haveround shape and are less densely packed, there.
Comparison of sake-brewing rice and table rice

The following equation states the rice-polishingratio, used to show the degree of polishing.

Weight of the white rice
Rice-polishing
×100
（%）
＝
ratio

28,342

Source: The results of agricultural product inspections of rice in 2020
(Ministry of Agriculture, Forestry and Fisheries)

Gohyakumangoku
Koshitanrei

Sake-brewing rice (Yamadanishiki )Weight of the brown rice

The table rice we normally eat has a rice-polishing ratioof approximately 90%. This means 10% of the exterior of
the grain has been removed as bran. We consume theremaining 90% as white rice.The specially designated sakes
are classiﬁed according to the rice-polishing ratio. They are
required to be made of rice of the following rice-polishingratios: Honjozo-shu, up to 70%; ginjo-shu and jummai-ginjo-shu,
up to 60%; daiginjo-shu and jummai-daiginjo-shu, up to 50%.
Jummai-shu is a special case with diﬀerent requirements.

tokyo

120

Starch100

Omachi

Miyamanishiki
Hitogokochi
The main areas where sake-brewing rice is grown andthe amounts inspected

Sake-brewing rice has large grains and often has an opaque
white core called shimpaku in the center of each grain.
Sake-brewing rice is lower in protein content than tabler ice. T he g ra i ns brea k dow n easily du r i ng t he long,
low-temperature fermentation process, resulting in goodand consistent fermentation.Polished white rice, not brown
rice, is used to make sake.
The outer part of brown rice contains lots of lipids,
minerals and protein. Too much of these components willcause unpleasant ﬂavor. Thatʼs why these parts must be
removed by rice polishing.

80

ProteinRatios tobrown rice 60（%）

Sake-brewing rice
Table rice40

Minerals

200Lipids

Brown
rice

90

80

70

60

Rice-polishing ratio（%）

50

Changes in proportions of components caused by rice polishing

Yamadanishiki(Sake-brewing rice)
Brown rice

Rice-polishing ratio 65%

Rice-polishing ratio 45%

Yamadanishiki

Yamadanishik i is a sa ke -brew i ng r ice t hat was cross-bred i n Hyogo
P refect u re.Yamadanishik i was developed i n 1936 t h roug h 13 yea rs ofcultivation tests af ter cross-breeding at t he Agr icultural Ex per iment
St at ion, Hyogo P refect u re. A l l of Japa ne se Toji (ch ief sa ke brewer s)
especially prefer to work with this variety of rice because it produces good
tasting sake with good physical properties.It grows up to 130cm and theears bow archwise at the time of harvest.Yamadanishiki accounts for 33% of
the sake-brewing rice har vested in Japan. Approximately 60% of it isproduced in Hyogo Prefecture (the result of agricultural product inspectionsof rice in 2020).
02

Ears emerge,
blooming

Flowers

Just before harvest

Rice steaming

Koji making

Rice processing

Washing, soaking and steaming rice are referred to as riceprocessing.Well steamed rice is the basis of good sakebrewing. It is a process sake brewers are very sensitive to.The
moisture content in steamed rice has a signiﬁcant impact,
almost single-handedly determining the quality of the ﬁnishedsake.Too much moisture content will cause the rice to break
down too much during fermentation, and therefore produce
too many components of taste.If the correct balance between
the decomposition level of the steamed rice and the alcoholic
fermentation by yeast is not achieved, it becomes diﬃcult toﬁne-tune the ﬂavor of the sake.
In order to produce steamed rice with the appropriate
moisture content, ﬁrst we must precisely control the amountof water to soak the rice before steaming.For the purpose, wehave to ascertain the quality of the rice, measure the watertemperature, try a test-washing, and determine the correct
length of time to soak the rice. By precise control we meanachieving a 1% level of accuracy of the amount of water
absorbed.Controlling the water content of rice by means ofcurtailing soaking time is referred to a Gentei-Kyusui (limited
water absorption).Especially for ginjo making, the entire
brewing staﬀ joins the process of washing rice, soaking it, anddraining it, in order to hit the precise water absorption target.

Washing
Rice grains that are especially highly
polished (with low rice-polishing ratio)
tend to crack easily. This type of rice
has to be washed with cold water
quickly and carefully so as not to crackt h e g rain s . O n c e t h e g rain s a recracked, it will be diﬃcult to adjust theamount of water absorption.
Left: Soaking (letting rice soaked sothat it absorbs water)
A black tray is ﬂoated on water tocheck the water absorption.

Water

Approximately 80% of sake is water.In order to makedelicious sake, we must obtain very high quality water that
does not contain iron, because iron causes coloration of thesake.This section describes the water used by sake brewers in
the two largest sake-brewing areas in Japan: Miyamizu (Miyawater) in Nada and Gokosui (Goko water) in Fushimi.
Miyamizu in Nada
In the latter part of the Edo era, Mr. Tazaemon Yamamura,
who had sa ke brewer ies i n Uozak i, Kobe, a nd a lso i n
Nishinomiya, wanted to ﬁnd out why his Nishinomiya brewery
always produced higher quality sake than his Uozaki brewery.

Sake

Pressing

Fermentation

The Storyof Sake

He changed toji (chief sake brewers) and tools of Uozaki withthose of Nishinomiya, but this did not provide reliably goodresults. In 1840, when he brought water from Nishinomiya to
Uozaki to make sake, the Uozaki brewery produced goodquality sake.Rainwater on Rokko Mountain inﬁltrates into thesoil and ﬂows out of springs aroundthe Nishinomiya Shrine. This springwater is the secret for the productionof excellent sake.From that time,sake brewers in Nada began to use
Nishinomiya water.People abbreviatedthe water from Nishinomiya: “Miyawater” ‒ Miyamizu.Miyamizu is hardwater. Sake made in Nada using thishard water has a dry and crisp taste,
so it is referred to as Otoko-zake(Menʼs sake).

Stone monument at the birthplaceof Miyamizu (Nishinomiya City).

Gokosui in Fushimi
Fushimi in Kyoto City is a land blessed with a large amountof good quality underground water.One place where this water
emerges from the ground is at Gokonomiya, a shrine near
Momoyama-goryou-mae Station on the Kintetsu Kyoto line. The
water from this spring is called Gokosui.This shrine was named
after Gokosui (perfumed water) by theEmperor Seiwa, because water with apleasant aroma sprung up in thissh r i ne on September 9, 8 62.I n
Fushimi, in addition to Gokosui (alsocalled Iwai-no-Mizu) there are six
other sites where good water can befound. They are called the “seven
wells of Fushimi.”Gokosui has lesshardness than Miyamizu in Nada.
Sake made with this water is smoothand silky, so it is called Onna-zake(womenʼs sake).
Gokosui(Fushimi-ku in Kyoto City)

Gokosui
in Fushimi

tap waterin Tokyo

7.1

6.4

7.5

51

8.4

ー

3.5

7.3

5.5

ー

87

157

44

43
3.1

Uozaki

Nishinomiya

pH

6.9

Calcium

29

Magnesium
Hardness
Sodium11

25

11

Potassium

2.8

9.8

1.9

ー

Chloride

10

35

7.3

1.8

0.3

4.4

ー

0.0

<0.005<0.005ー0.12

Phosphoric acid
Iron

Unit: mg/L (except for the pH)

Comparison of the qualities of water from Uozaki, Nishinomiya, Fushimi, and Tokyo.
The World Health Organization (WHO) Drinking
Water Quality Guidelines:
Soft water: Hardness of 60 mg/L or lessMedium-hard water: Hardness of 60 to 120 mg/L
Hard water: Hardness of 120 to 180 mg/L

Source: The Journal of Brewing Societyof Japan: Vol. 87, p.909 (1992), theBureau of Waterworks Tokyo Metropolitan
Government (2015).

03

Sake Brewing

Rice forsake making

RicepolishingRicewashingand soaking

The Integration of Scienceand Technology

Koji mold (Aspergillus oryzae)

Koji mold has been named the National Fungi of JAPANby t he Brew ing Societ y of Japan. It has been used to
produce sake since ancient times.Besides being used forsake brew ing, koji mold is also used for mak ing suchtraditional Japanese products as shochu (a Japanese whitespirit), awamori (an Okinawan spirit made with black kojionly), miso, soy sauce, vinegar, and pickles.

Hypha
20μm

Koji mold spores (Also known as conidia

Photo by Moriyuki Kawauchi)

Enzymes

Koji is cultured koji mold on
rice, barley, beans, and so on.
Rice koji, used for making sake, isof course grown on rice.Koji
mold digests the rice using
enzymes, converting starch to
glucose. Then yeast eats the
glucose to carry out the processof alcoholic fermentation.

After inoculated on the surface ofsteamed rice, the spores of koji moldgerminate and extend their hyphae.The
tips of the hyphae secrete enzymes.

Making koji (seikiku)

After washing, soaking and steaming of rice, the next
step in brewing sake is making koji.
There are two well-known features for growing koji.One
is t he Soha ze-Koji cond it ion. T h is is when t he k oji isentirely covered w it h hy phae of koji mold called haze
which looks like white. The other is called Tsukihaze-Koji.
This koji has some haze area on the surface which has
grown into the steamed rice. Both of them are considered
to be good k oji.G enera l ly tsuk ihaze-k oji is used whenbrew i ng g injo - sh u.Tsu k iha ze - k oji i s e spe cia l ly r ich i n
glucoamylase, which breaks down starch into glucose,and it does not have so much protease, which breaks
down protein into amino acids that impart taste.Therefore,
the tsukihaze-koji can supply enough glucose to nourish
t he yeast, per m itt ing a long last ing fer ment at a lowtemperature. Sake made with this koji turns out a lightand delicate taste.

Enzymes are functional proteinsthat break down various substances.
Cuts here

Surface

Surface

Cuts here
Starches, proteins

Sugar, amino acids,
and so on.

Haze

Cross section

The safety of koji mold

Hazekomi(Haze intrusion)

Cross section

Koji mold, which has been named after the National Fungi of JAPAN,
can be classiﬁed into three types, according to color.Yellow koji mold
(Aspergillus oryzae) is chieﬂy used for brewing sake. Black koji mold
(Aspergillus luchuensis) is chieﬂy used for brewing shochu and awamori.
Tsukihaze-koji
Sohaze-koji
White koji mold (Asperigillus kawachii) is a mutant strain of black koji
(Higher enzymatic activity,(Higher enzymatic activity,
mold.There are actually many mutant strains of each koji mold.
Light and delicate sake taste)
Rich and full-taste sake)
Yellow koji mold grown on rice has been used since ancient age for
Tsukihaze-koji and sohaze-koji
brewing sake.In 1960, it was reported in the UK that some strains ofAspergillus flavus, a species related to yellow koji mold, produces aﬂatoxin,
which is a kind of mycotoxin. So, it came to a matter that even yellow koji mold might produce aﬂatoxin.NRIB immediately began to research this issue.
In 1971, we clearly determined that the yellow koji mold group is diﬀerent from the Aspergillus flavus group, and that yellow koji mold does not produce
aﬂatoxin.This research proved that sake made with yellow koji mold is safe to consume.Then, in 2009, research at the genetic level proved that yellow kojimold does not generate aﬂatoxin.
Also black and white koji molds had already been conﬁrmed to be safe.It was reported in 1994 that some strains of Aspergillus niger, a relative of thesemolds, produces ochratoxin, a kind of mycotoxin.We analyzed black koji mold, white koji mold, and Aspergillus niger in 2009 on the genetic level. We
proved that black koji mold and white koji mold belong to a diﬀerent group from that of Aspergillus niger, and that they do not produce ochratoxin or
aﬂatoxin. We continuously conduct research on the safety of not only koji mold but also yeast and sake itself, as well as the eﬀects of sake on humanhealth.

Aspergillus flavus
Aspergillus oryzae
Aspergillus niger
Koji mold(From the left), yellow,
white and black koji molds

04

Aspergillus luchuensis
Aspergillus kawachii

Aspergillus
phylogeny

Rice steaming

Koji making

Fermentation

Excessively steamed rice is unable to grow good koji.
Sake brewers control moisture content and temperature
to produce sohaze-koji or tsukihaze-koji according to the
aimed quality of sake. It takes approximately two days togrow koji.
On the ﬁrst day, the steamed rice is cooled down to theappropriate level and brought into the koji-making room.
Then the steamed rice is spread on a table called toko,
a n d k o ji m o l d s p o r e s a r e s e e d e d a c r o s s t h e e nt i r esurface.After the spores are seeded, the steamed rice iscovered with a cloth to maintain the correct temperatureand humidity. The rice rests for that ﬁrst day on the toko.
During this stay, the koji mold spores germinate.The ﬁrst
day is referred to as the toko period.
O n t h e s e c o n d d a y, t h e k o j i b e i n g p r o d u c e d i s
t r a n sfer re d i nto sh a l low t r ay s, c a l le d k oji- ba k o a nd
koji-buta.This transfer task is referred to as mori.Amountof koji for a koji-bako is 15 to 30 kg, and for a koji-buta is
1.5 to 2.5 kg.As the hyphae of the koji mold grow, theyg e n e r ate h e at , s o t h e b r e we r s h a ve to c o nt r o l k o ji
temperature to avoid it rising too much.The second day,when the koji mold is kept in the trays, is called the tanaperiod.

Koji making (from the left, the koji-bako and koji-buta)

W hen t he temperat ure of t he koji reaches 4 0 to 43
degrees Celsius, and after 43 to 45 hours (or sometimes
more than 48 hours when using the tsukihaze-koji process)has elapsed since t he r ice was broug ht into t hekoji-making room, koji making is complete.Good koji has asoft elasticity when grasped by the hand and it does not
stick to the hand after being released.With good koji, youexperience a light sweet taste and an aroma like roasted
chestnuts.

Yeast

The alcohol in sake is madeby yeast.There are many kindsof yeast living in the naturalenvironment. Natural yeasts
grow on fruit juice when a fruit
is injured.A lso t here is w ild
yeast adhering to brown rice
and white rice grains.There aremany kinds of yeast. Some oft hem are used for mak ing
bread, others for making soy
sauce and for making miso.The
ye a s t c a l l e d S a c c h a r o m y c e s
cerevisiae is the chief one used
for brew i ng sa ke. T he ter m“saccharomyces” comes fromthe words for sugar andmushroom in Greek. The term

Sake yeast
Yeast grows by the budding andseparating of daughter cells frommother cells.
During sake brewing, yeast multiplies
as much as 20 thousand times. One
gram of fermentation mash ﬁnallycontains approximately 200 million
yeast cells.

The Storyof SakeSakePressing“cerevisiae” comes from the Latin for beer.
Yeast generates ethanol and carbon dioxide gas fromt he glucose t hat t he koji made by break ing dow n t he
st a rch i n t he r ice. Ye a st a l so pro duce s ma ny ﬂ avor
components, in addition to ethanol.
Starches, proteins, fats

Rice koji

Enzymes
Glucose, amino acids, fatty acids

Vitamins
Aroma components
Alcohol
Esters(Ginjo-aroma)

Yeast

Taste components
Organic acids
Amino acids

Ethanol, carbon dioxide

The functions of koji mold and yeast in sake brewing

The aroma and taste components produces by yeast
vary with each yeast type, so the aroma and taste of sakedepend on the speciﬁc yeast used.Therefore, the selectionof puriﬁed yeast from ferments of good sake batches has
been car r ied out, accompanied by fer mentat ion
te st s. S i nc e 19 0 6, t he ye a st t hu s s e le cte d h a s b e e n
distributed as “Kyokai sake yeast” by the Brewing Societyof Japan.
O n e a m p u l e (a p p r ox i m ate l y 10 m L ) i n t h e p h oto
contains approximately
20 billion yeast cells. If
you ferment one ton ofrice using this one
ampule for starter
culture and thenfermentation mash, you
can make approximately
1,200 bottles (using 1.8
L bottles) of jummai-shu.
Kyokai sake yeasts arenumbered in ascending
numerical order
Kyokai sake yeast (ampule)according to theirlaunching. Nowadays, K-6, K-7, K-9, K-10, K-11, K-14, andK-18 01 a r e o f t e n u s e d . T h e s e y e a s t s a r e c l o s e l yrelated,genetically. However, each sake has a diﬀerent
aroma and taste. They are used selectively to attain adesired goal regarding the qualities of the sake being
produced.It is said that the aroma of ginjo-shu has become
especially ﬁne since “Kyokai sake yeast K-7” came intou s e ( i s o l a t e d i n 19 4 6 ) . K-7 f e a t u r e s a v i g o r o u sfermentation and pronounced aroma. Even nowadays thisyeast is still widely used for brewing sake.From toward
1975, “Kyokai sake yeast K-9” has played a major role in
the production of ginjo-shu. Its wonderful aroma as well
as mild and smooth taste has established the st yle ofginjo-shu.Recently, “Kyokai sake yeast K-1801” is being
used, featuring an apple-like ethyl caproate aroma and amild taste with low acid production. Unique yeasts bredin the various prefectures are used to make many typesof sake, including ginjo-shu.

05

Sake Brewing

Rice forsake making

RicepolishingRicewashingand soaking

The Integration of Scienceand Technology

Shubo (Starter culture)

What features are necessary for starter culture? First,
starter culture should contain a great deal of yeast. Second,
starter culture has to have the appropriated level of acidity.
An acidic condition helps prevent the increase of bacteriathat can spoil the main fermentation. This phenomenon issimilar to the process of making pickles, which is a way ofstoring vegetables in vinegar to prevent their spoilage bybacteria. There are two methods for making the starter
culture acidic: using a lactic acid fermentation process, andusing lactic acid specially prepared for brew ing. T he
representative method of using a lactic acid fermentation
process is called “kimoto (kimoto starter culture).” The
representative method of using lactic acid is called “sokujo(sokujo starter culture).”KimotoKimoto is the technique developed in the Edo era (1603 to1867) for growing yeast using natural microorganisms.The
ﬁrst step in the kimoto process is to put 14 to 15 kg ofsteamed rice, koji,
and water into atub, called hangiri,
at a temperatureof 8˚C.After a few
h o u r s , t he r ice
grains swell withabsorbed water.
The workers stir
the mixture insideof t his tub well,every a few hours.
Yamaoroshi (tub (hangiri) and paddle (kai))On the next day,they grind the rice using a tool shaped like a paddle,called
kai.This grinding operation is called Yamaoroshi.It is very
hard work for two or three workers to grind a tub of rice ina cold room, three times a day.After it is well ground, they
move the mash into a tank, where itʼs kept for 3 days at 6 to
7˚C.This period is referred to as utase. Nitrate-reducing
bacteria that were in the starter culture gradually change
the nitrate in the water to nitrous acid.This nitrous acidsuppresses the multiplication of the wild yeasts.
Five or six days after the ingredients were initially put inthe tank, the warming of the mash begins.A cask full of hot
water is put into the tank, kept for 2 to 3 hours and thenremoved. This process is repeated at an increasing rate of
approximately 1˚C per day.
A s t he temper at u re r ise s, t he lact ic acid bacter ia
g radua l ly become act ive a nd sta r t to produce lact ic
acid.The combined actions of the lactic acid and nitrousacid cause the ﬁlm yeast and wild yeast to die oﬀ.Then, as
the lactic acid increases, the mash becomes so acidic that
06

Starter culture
temperature

20(Logarithmic)

76
5Sake yeast

Lactococcus

815

Nitrate-reducing
bacteria

104Lactobacillus

3
2
1
0

5

Wild yeast
Film yeast

Start(Put in the ingredients)

5
10
Yamaoroshi Utase Warming

15
Add sake yeast

25

20

Starter culture temperature

9

The number of bacteria

After the koji making has ﬁnished, the next step is toprepare the sake starter culture. Just after the starter
culture is prepared, wild yeasts remain in the culture, in
addition to desirable sake yeast, like Kyokai sake yeast.
While the rice koji is being made, these wild yeasts increase
as well. However, some wild yeasts (for example, ﬁlm
yeasts) produce unfavorable components that smell likepaint thinner or vinegar, and others stop the process of
alcoholic fermentation. For sake brewing, we must use
excel lent ye a st t hat fer ment s at a low temper at u re,generates a great deal of alcohol, and results in sake with agood ﬂavor. The propagation process of selected yeast,
shubo, ensures a good fermentation of sake.

（℃）
25

(Day)

Cooling

The transitions of microorganisms in a kimoto-style starter culture
The kimoto-style starter culture was a great technique.
This allowed brewers to grow pure sake yeast by the intelligent use of thenatural transitions of microorganisms, where the types and numbers of
microorganisms change as shown in the ﬁgure above.

the nitrate-reducing bacteria also die oﬀ, and the remaining
nitrous acid isconverted.
A s t he acidit y
increases further,even t he lact ic
acid bacteria ﬁndthemselves in an
unfavorable
environment, andt hey die oﬀ, aswell.At this stage,t h e a m o u n t s o f Warming（In this process, the workers turn awarmer with their hands.）
sugar and aminoacids in the mash have increased, and so the mash is theideal environment for growing of the sake yeast, which iswell able to tolerate acidity.
Therefore, now is the time to add previously cultured
sake yeast to the mash.In the past, the natural yeast thatwas speciﬁc to each brewery grows there, or the brewer
retained some already fermented starter culture to add to
his mash, continuing his established line of yeast.During
the last half of the starter culture process, the remaining
lactic acid bacteria are killed by the alcohol that is being
generated by the yeast. As a result, ﬁnally only sake yeast
remains in the culture.
Yamahai (Yamahai starter culture): a modified type of kimoto
Some bottlers of sake have Yamahai or Yamahai-Shikomi
written on their labels.Yamahai is the abbreviation foryamaoroshi-haishi. This name was chosen to indicate thatyamaoroshi, the most arduous work in the kimoto process,had been done away with. In the yamahai method, steamed
rice is broken down by koji enzymes, not by the physicaleﬀort of the workers using their paddles.This process saves
the time, labor, tools and space needed to grind the rice
during the kimoto operation. This method was developed in1909 by our institute.There is not much diﬀerence between
the kimoto and yamahai processes, in terms of the ﬁnal
quality of the sake or the character of the yeast used.

Rice steaming

Koji making

Fermentation

SokujoKimoto was a very successful technique established by ourpredecessors in the era when they did not know that sakewas made by microorganisms. However, some lactic acidbacteria that would remain in their starter could spoil thesake. These harmful bacteria may multiply if the starter
culture-making operation is not appropriately controlled.In
the past, it had often happened that a warm winter resulted
in contamination of the starter culture by harmful bacteria,
and the fermentation mash would be spoiled.The mash canno more properly ferment due to infection than rice orvegetable can grow due to disease.Another consideration
involved in the starter culture-making process was thatmuch care and labor was required during the long period offour weeks to create the kimoto.
Then, in 1909 we developed the method to produce
starter culture by adding very pure lactic acid (brewing
l act ic ac id ) to s ub due t he g r ow t h a nd act i v it ie s of
microorganisms. Simultaneously the yamahai process wasdeveloped.With kimoto, it takes two weeks or so to produce
lactic acid by lactic acid bacteria. Using very pure lactic
acid saves this period.This method produces starter culture
much faster, so it is called sokujo (rapid production of starter
culture).Currently, most sake is made through this sokujo
process.

Moromi (Fermentation mash)

Fermentation mash is prepared by the addition of water,
rice koji, and steamed rice to a starter culture, and thenactual sake fermentation starts.
The size of a batch of sake manufacture is shown by theweight of the white rice used. A small batch is one of abouta hu nd r e d k g , a nd a l a r ge b atc h c a n b e 10 ton s or
more.Normally, a fermentation tank has a capacity threetimes the volume of the amount of rice used. If a sake batchis 10 tons or more, a fermentation tank with a capacity of
3 0 k L or la r ger i s ne e de d to hold t he fer me nt at ion
mash.The standard relationship between the steamed riceand the rice koji in a fermentation tank is 77 (rice) plus 23(rice koji) (where the white rice is measured in kg), plus 130
liters of water.
The whole vat of fermentation mash is not prepared atonce. It is prepared in successive stages, by dividing thetotal into three portions, prepared over four days.This
process of preparing the fermentation mash with gradually
increasing three portions is referred to as sandan-jikomi(three-step preparation of fermentation mash).This is done
Water

Steamedrice

Pressing

Sake

The Storyof Saketo prevent a delay in the production of alcohol by diluting
the yeast too much, and to prevent the growth of unwanted
bacteria.
The 1st day is referred to as soe (ﬁrst addition). The 2nd
day is odori (the next day after soe), which is when theworkers wait for the yeast to grow.The 3rd day is naka
(second addition) and the 4th day is tome (third addition).
Low temperature fermentation is appropriate for brewng
sake.The low temperature controls the activity of yeast andallows the alcoholic fermentation to progress steadily,resulting in ﬁner quality and more delicious sake.
Fermentation takes place at 10 to 18 C generally.About
one week after the third addition, fermentation becomes
active. Then, fermentation settles down after three weeks,
when the alcohol has reached 18 to 20 percent.

Foaming yeast and non-foaming yeast
Normally, sake yeast produces a layer of foam thatcovers the surface of the fermentation mash from 4
to 10 days af ter t he t hird addition.T his was acharacteristic of sake yeast. However, non-forming
yeast was reported independently by NRIB and theHiroshima Regional Taxation Bureau in 1916.
No foam layer means that brewery workers do not needto clean foam oﬀ their tank walls.They also do not need to
wor r y ab out over ﬂow i ng foa m du r i ng act ive
fermentation.In case of non-foam-generating-mash,
fermenting tank could accommodate more mash thanfoam-generating-mash by the volume of form.There aremany beneﬁts to using non-foaming yeast, butmanufacturers did not consider using it when it was ﬁrst
discovered.
Then, in 1963, the demand for sake exceeded theexisting production capacity, and people saw that
non-foaming yeast could contribute to increasing
production capacity within the same facilities.
The staﬀ at NRIB developed a breeding method of
non-forming yeast, and eventually succeeded in
obtaining a mutant non-foaming yeast from “Kyokaisake yeast K-7.”In 1971, this mutant yeast was named“Ky o k a i s a ke ye a s t K-7 01,” a n d it we n t i n to
distribution.Now, a great deal of sake is brewed with
non-foa m i ng ye ast. T h is re se a rch was a re a lgame-changer for the sake industry to ﬁnd a way “tocreate” a new yeast, in addition to “to select.”Then, we continued researching into foam madeby yeast, and ident iﬁed t he AWA1 gene t hat is
responsible for forming of yeast.On the basis of thisﬁnding, we are now able to grow other non-foaming
yeasts, because we can check various yeasts for thepresence and expression of the AWA1 gene.

Starter
cultureRice koji(1st day only)
Third addition(tome)

4th day

Second addition(naka)

3rd dayFirst addition(soe)

1st day

Three-step preparationof fermentation mash

Foaming yeast

Non-foaming yeast07

Pressing and finishing
Joso (Pressing)

Pressing is the process used to separate the matured
fermentation mash into sake (the liquid) and sake cake (thesolid).Sake cakes consist chieﬂy of the rice, koji and yeast
remaining after the fermentation.During this pressing process,it is important to keep the temperature low, avoid too muchpressure, and avoid the sakeʼs contact with the air as much as
possible. Sa ke, as well as ot her a lcohol ic beverages,
deteriorates in quality through the eﬀect of oxygen in the
air.There are various methods to press sake. One method is to
put the fermentation mash into a tube-shaped cloth bag calledsaka-bukuro and hang it so the sake drips out. Another method
is to use a pressing device such as a traditional press ( fune) oran automatic ﬁlter press for sake.
When you use a fune, you lay some cloth
bags ﬁlled with fermentation mash at thebottom of the fune and then stack more
cloth bags on top.Stacking up the cloth
bags causes the weight of themselves topress the fermentation mash. The naturallypressed sake drains out of a tap.T heﬁrst-running sake is cloudy, but as thecloth weave is ﬁlled with residual solids it
f unct ions as a ﬁ ne ﬁ lter so t hat t helater-running sake becomes transparent.
The ﬁrst-running sake is referred to asarabashiri (free run sake).Once the speed ofsake being naturally pressed reduces, we
Fune (a traditional press)
use a press.At the top of the fune hydraulicunit is equipped, that presses
the fermentation mash bygradually raising thepressure on the clothbags.The ﬂavor of drained
sake changes little by little,
depending on the time
elapsed and diﬀerences inpressure level, even though
it is coming from the same
Cloth bags holding fermentation mash
run of fermentation mash.
are stacked on the fune.
When pressing using an automatic ﬁlter press for sake, thefermentation mash pours in
between vertical plates towhich ﬁltration cloths areattached. High-pressure air is
fo r c e d i nto r u b b e r b a g s
attached to the plates. These
rubber bags inﬂate and applypressure to the fermentation
mash from both sides.
Automatic ﬁlter press for sake

Oribiki (Removal of sediment), filtration
Soon after pressing, sake is a cloudy white, as shown in theupper right.The cloudiness is caused by ﬁne particles of yeast,
rice, and rice koji. This is referred to as the ori (sediment).

08

Pressing

Removal of
sediment

Filtration

Oribiki is the process of removing thesediment from the sake after pressing.The
sake yeast in the sediment is still alive
after pressing. It can restart fermentation
within a certain temperature range, or go
into self-digestion (resulting in its death).
In addition, the components in sake will
be changed over time by the enzyme
act iv it ies der ived f rom koji and sakeyeast. Leaving the sediment in the sake
Sake soon after pressing
for a long time may increase the amino (free run sake (arabashiri)acids and sugar, causing deterioration of When the sake is stored
a low temperature, andt h e s a ke ʼs q u a l i t y.G e n e r a l l y, a f te r at
white hazes settle to thepressing, sake should be stored at a low bottom of the bottle.
temperature. When the sediment sinks, it is removed fromthe sake.The ﬁrst removing is generally done ﬁve to ten days
after pressing.The amount of sediment will depend on eachpressing method used. Only a small amount of sedimentremains after pressing using an automatic ﬁlter press forsake. Therefore, some brewers dismiss the process of
sediment removal after using this pressing method. In thiscase, any remaining sediment is removed by a ﬁltration
machine.
Filtration is used to remove ﬁne particles (sediment andmicroorganisms) suspended
in sake through a ﬁne meshﬁ lte r.T h e r e a r e d i ﬀ e r e nt
ﬁltration methods speciﬁc torespective purposes: ﬁltration
to remove sediment, ﬁltration
after activated carbon
treatment to adjust ﬂavor,
and ﬁnal ﬁltration performed
Filtration machine
just before bottling.
Activated carbon for brewing is added into sake to adjust
ﬂavor.There are a lot of extremely tiny pores on the surfaceof the activated carbon, which absorb coloring matters,
bitter taste and smell constituents.Coloring matters andoﬀ-ﬂavor constituents are removed ow ing to physicalproperties of activated carbon. Therefore this techniqueenables us to prevent coloration and over-maturation of sakecaused by heat and light.Just after being pressed, the colorof sake is light yellow. After activated carbon treatment andﬁ lt rat ion, t he sa ke is almost colorless a nd qu ite
transparent.Whether or not to use the activated carbon andhow much is that used are subject to the target quality of thesake.

Hi-ire (Pasteurization)

In pasteurization process, sake is heat-sterilized to assure
microbial stability and product quality.Freshly pressed sakehas a unique fresh deliciousness. However, the enzymes
derived from the koji and sake yeast are still active.Freshsake is quite unstable in quality. Over time, it is likely to get
sweeter and develop an oﬀensive smell, called namahine-ka or
mure-ka.These enzymes cannot be removed by sedimentremoval and ﬁltration.In addition, hiochi bacteria (some kindsof lactic acid bacteria that are tolerant to alcohol) can growin fresh sake, deteriorating its quality.This is why the sake isPasteurization

Storage

Blending,
Adding water

Bottling

heated to about 60 to 70˚C, which kills the hiochi bacteria
and inactivates the enzymes. This stabilizes the productʼs
quality.
I n general, sa ke goes
through two pasteurizations
steps.The ﬁrst pasteurizationis performed before storage,
and the second one is done
just before or after bottling.
There are two methods ofpasteu r i zat ion. One is to
apply heat to sake by heatexchangers equipped between Heat exchanger (for pasteurization)
hoses linking tanks and bottle-ﬁllers. The other is to heatbottles ﬁlled with sake.
Usually, heat exchangers are used to pasteurized sake.On
the other hand, heating sake in bottles provides so precise
temperature control that this method is especially used for
ginjo-shu.Heating in the bottle prevents loss of the fruity
ﬂavor, and so the typical ﬂavor of ginjo-shu is well retained.
A l l t he sa me, t here a re a lso non-pasteu r ized sa kebrands.A sake stored, bottled, and shipped without any
pasteurization is called unpasteurized sake (nama-zake).
Typically, nama-zakeis protected f rom
Freshly pressed sakequality degradationby c old stor age or
Pasteurization
special ﬁltration.This
let s you e njoy t he
Storage
Storagef resh taste of sa ke
owing to being
Pasteurization
Pasteurization
u npasteu r ized.I n
a not her va r iat ion, Bottling Bottling Bottling Bottling
there is also sake thatis pasteurized before
sake
fresh-stored sake unpasteurized sakeStandard fresh-bottled
namazume-shu
namachozo-shu
nama-zakestorage, but not
Shipping
before bottling.Thisi s r e f e r r e d t o a s Number of pasteurizations and classiﬁcations of sakef re sh - b ot t le d s a ke
(namazume-shu).A sake that is not pasteurized before storage
but i s p a ste u r i z e d b efor e b ot t l i n g i s r efe r r e d to a s
fresh-stored sake(namachozo-shu).

Storage
After it is ﬁrst pasteurized, usually sake is stored in a storagetank.In the storage tank, the sake sits quietly and matures.
This will increase its good matured diﬀerent ﬂavor andsmoothness from freshly pressed sake.It is important to keep
the tank temperature quite constant, to promote stablematuring.

Shipping

The Storyof Sakestorage tanks to as the next ﬁltering and bottling processes.
Water may be added to sake in order to adjust its alcohol
content.Just after pressing, sake has relatively high alcohol
content, around 18 to 20%. Water is added to reduce alcohol
content level to 15 to 16%, which is suitable for drink.The
same high quality water as brewing water is used to dilutesake.
On the other hand, there is also sake without being
diluted.This is referred to as undiluted sake (genshu).In general,
genshu has a rich taste, but you should be careful not to drink
too much! It has a high alcohol content.

Bottling, shipping
Bottling is the ﬁnal process of brewing sake as a commercial
product.Particular attention must be paid to the maintenanceof a hygienic environment, to prevent contamination byforeign material and microorganisms.Therefore, somebrewer ies clearly separate the bottling area from the
manufacturing area where koji mold and sake yeast arehandled, or place the bottling area in a separate location (oreven another building).
Special machines are used for bottling to ﬁll the bottles up
to the speciﬁed amount.Pasteurization is performed atbottling, except when brewing unpasteurized sake (nama-shu)
and fresh-bottled sake (namazume-shu). When heated sake wasbottled,it pasteurizes both the bottles and the sake in thebottle, and the air is pushed out of the bottles by the steam
emitted from the sake, thus decreasing the amount of oxygen
inside.Therefore, this prevents deterioration by oxidation as
well as by bacteria.

Pasteurization of bottles

Filling machine

After bottling, labels are put on the bottles. The sake is now
a completed as a commercial product.The labeled sake bottles
are packed in cardboard boxes or special plastic crates forshipping.

Blending, adding water

Blending is the process of mixing sakes from in diﬀerent
tanks. Even if the same rice, koji mold, and yeast are used,the components of sake may vary because of the variationin rice treatment and temperature proﬁles during the koji
making and fermentation.In order to ship stable quality sakethroughout the year, manufacturers blend diﬀerent runs ofsake.Blending is carried out when the sake is moved from09

Enjoying sake
The maturation period
and flavor change
Hiyaoroshi, freshly pressed sake
Typically, sake is held for maturation in a tank or bottle
for from six months to a year, and then shipped throughout
the year.In general, higher temperature promotes fastermaturation. In the autumn, after being stored throughout
the summer, sake is moderately mature and has a mild
ﬂavor.A speciﬁc sake called hiyaoroshi is shipped during theautumn.Although there is no legal deﬁnition of hiyaoroshi, it
is a kind of namazume-shu that has been pasteurized before
storage, and that is not re-pasteurized when bottled andshipped in the autumn.
Some sake is shipped without being aged.Such freshlypressed sake can be found at sake breweries and in liquor
shops from the winter to the spring.Generally these fresh,
un-matured forms of sake are unpasteurized (nama-shu).
Long aged sake
Before storage technology was well developed, it was very
diﬃcult to retain the ﬂavor of sake at an acceptable level forover a year.Recently, thanks to the development of modern
technology and devices of storage, sake with unique ﬂavors
obtained after long intentional storage is made.They arewhat is called long aged sake.
Even if itʼs pasteurized, sake stored for a long time changes
its color to bright yellow and eventually to amber.This isbecause the reaction of sugar and amino acids in the sakecreates a colored matter called melanoidin.At the same time,
the aroma changes to a complex one with nuance of caramel,honey, nuts, and spices.This is believed to be the result of thereaction of sugar and amino acids which combine through theMaillard reaction, as well as from the break-down of aminoacids.The ﬂavor gradually becomes smoother. Due to someincrease in bitter-tasting components, the sake develops acomplex ﬂavor and r ich body, and it has a feeling of

0 years
Color

Filtration

Removal of
sediment

Pressing

20 years

Colorless,transparent

26 years

Amber

Aroma ・Fruity aroma
・Floral・Like koji, etc.

・Honey, soy sauce

Taste ・Lightness
Mouthfeel・Freshness

・Sweetness
・Bitterness
・Smoothness
・Complexity, etc.

・Nutty, spicy
・Sulfurous

・CoarsenessThe changes of characteristics during the storage of sake

expanding volume that is diﬀerent from the sake before
storage.
Well-structured sake like jummai-shu, after being stored for along time, can achieve a deep color, complex ﬂavor, and richbody.Sakes with a delicate taste and aroma, like ginjo-shu, areoften stored at a low temperature. After long storage, they
have a light color, mild ﬂavor, and a light and delicate taste.
Aged sake (koshu) is contrasted with new sake, and refers tosake brewed before the last brewing year (brewing year isfrom July 1st to June 30th of the next year).Among long-termstored sakes, those stored for an extremely long period arereferred to as greatly aged sake (daikoshu, ohgoshu). Sakes stored
longer than 5 years are sometimes called treasured sake(hizo-shu).

Oﬀ ﬂavors in aged sake (hine-ka) versus a matured aroma
In the past, some aromas that developed in sakeduring storage and distribution were referred to as oﬀ
ﬂavors of aged sake (hine-ka). Hine-ka may containvarious aromas. If, after a rather short storage anddist r ibut ion per iod, t he sa ke smells like takuan, aJapanese pickle, then the sake is considered to havedeteriorated in quality.On the other hand, if a smell likecaramel comes from long aged sake (held for a numberof years and even decades), this is called the matured
aroma ( jukusei-ko). This aroma was recognized as apositive feature of long aged sake.However, oﬀ ﬂavors
and matured aroma were not well distinguished even bysake experts.
Therefore, our institute set about re-deﬁning hine-ka asoﬀ ﬂavors which are diﬀerent from matured aroma, andb e g a n r e s e a r c h i nto t he s e t wo a r om a s.W h at we
discovered is that hine-ka chieﬂy consists of dimethyl
t r isulﬁde ( DM T S), while t he caramel-like smell of

10

matured aroma is related to sotolon, which is as known
as the main ﬂavor compound of aged sake.
We went on to research t he cause of t he hine-ka
compound, DM T S, and found t hat yeast creates a
precursor of DMTS (DMTS-P1). Also, various brewing
conditions inﬂuence DMTS formation.
Even now, we are engaged in research into how to
reduce DMTS ino r d e r to r e t a i n
Fermentation tanksakeʼs quality for
Generated during fermentation
longer periods.
O=

O

S

OH
OH

1,2-dihydroxy-5-（methylsulﬁnyl）
pentan-3-one（DMTS-P1）
The main precursors of DMTS

Changes duringstorage
S

S

S

DMTS
The maincomponents
of hine-ka

The DMTS-development process

Pasteurization

Storage

Blending,
Adding water

Bottling

Storing sakeIn order to preserve sakeʼs ﬂavor, it is important to store it
appropriately.In this section, we would like to explain how tostore sake at home.
Light, high temperatures and oxygen are the enemies ofsake.It is particularly the case that if sake is exposed to direct
sunlight, high temperatures or sudden temperature changes,
the sakeʼs quality will suﬀer.Therefore, the principle is to store
your sake in a cool, dark place.In addition, be careful andremember that even when a sake bottle is unopened, suchstrong odors as insecticide and soap can be transferred into
the sake.
M a ke s u r e yo u stor e s a ke t h at a r e l ab e le d “ ke e p
ref r igerated,” like nama-zake, in a ref r igerator all t hetime.Enzymes are still active in nama-zake, so it will losequality even faster than draft beer.Sakes other than thoselabeled “keep refrigerated” should be stored in a cool, darkplace. Keep them in their original packages: the paper rolledaround the bottle or the cardboard box.
How should we store the once-opened sake?Of course,
opened sake should be stored somewhere cool and not
exposed to light. But besides that, it will also be negatively
aﬀected by the oxygen in the bottle.It is recommended thatthe opened sake should be drunk as soon as possible.

The Storyof SakeShipping

The mechanism of sake deterioration – the effects of light andtemperature
It should be noticed that fermented liquor like sake, beer,
and wine deteriorate more readily than distilled liquor likewhiskey, shochu and vodka.
Why do these fermented liquors deteriorate easier thandistilled liquors?It is because they contain much more suchcomponents as sugar and amino acids.These components do
not evaporate by distillation. Therefore, they are not included
in distilled liquor.Sugar and amino acids are the ingredientsthat make the characteristic ﬂavor of sake. On the other hand,
they can also cause unwanted change of color, aroma andtaste.
You may ﬁnd it hard to believe that light alone could cause
deterioration of sake. Yet you know that ultraviolet rays in thelight can have remarkable eﬀects, like causing our skin to tan
or even bur n. It can t r igger chemical changes of t hecomponents in sake.Therefore, change of color, deteriorationof ﬂavor, and increased bitterness are caused.
OxygenLight(Sunlight, ﬂuorescent light)
Enhance deterioration

Temperature
Low ←→ High
Slower change Faster changeLight shielding
ability of containers
Low ←→ High
Transparent Brown bottle
bottlePaper package

The typeof sakeUnpasteurized sake(nama-zake)
Ginjo-shu
Sake containing a lot of amino acids

Deteriorates easily

Factors aﬀecting the deterioration of sake

The pairing of sake with diﬀerent foods
We are also carrying out the research about the pairing
between alcoholic beverages and foods.We found thats u l f u r ou s acid i n w i ne c au s e s t he ﬁ shy o dor a nd
bitterness from DHA contained in dried cuttleﬁsh.If you
try dried cuttleﬁsh together with white wine, you willprobably perceive a strong ﬁshy smell. However, if you
try it with sake, you may not perceive that smell much, orat all.This phenomenon occurs because sake does notcontain sulfurous acid or iron. Thus, we have showed thescientiﬁc reason why sake goes well with the ﬁsh andshellﬁsh that are the epitome of Japanese cuisine.

2.0

Fishy odor
Unpleasant taste

1.6

As strong as you can imagine
Very strong
StrongSake B

0.4

Sake CWeak

Sake A

0.8

Wine B

Neither strong nor weakWine C

1.2

Wine ALog Intensity of smell and taste

It goes without saying that sake alone tastes good, butfood enhance sake up to the outstandingly delicious
level.B y ex per ience, we k now t hat si mple t a st i ng
Japanese foods like boiled tofu ( yudofu) go well withsake.Each region has its own liking for tastes of saker a n g i n g f r om s we et to d r y, or f r om r ic h to l ig ht .
Therefore it is well-known that each local sake goes wellwith its own dishes.In France, the relationship between aparticular food and wine is referred to as “le mariage”(the marriage). In general, it is felt that white wine isgood to drink with chicken and ﬁsh dishes, and red wineis good to drink with lean meat dishes.
There is a lot of infor mation about the pair ing of
alcoholic beverages and foods, and there is also someunderstanding of the scientiﬁc reasons for these pairings.
Below is some information from a research report from aleading Japanese liquor manufacturer: 1) White radish inoden (Japanese hodgepodge) is good with sake, but notgood with either red or white wine. Camembert cheese
goes well with wine. 2) Good pairing occurs when both
the dish and the alcoholic beverages increase in positive
ﬂ a v o r, a n d a p l e a s a n t a f te r t a s t e i s c r e a te d .
Incompatibility results in an increased ﬁshy smell or abad taste experienced after tasting the dish. 3) Iron inwine accelerates the oxidation of polyunsaturated fatty
acids such as the docosahexaenoic acid (DHA) contained
i n ﬁ sh a nd shell ﬁ sh, a nd t h is generates ﬁ shy odor
compounds.

Degree of ﬁshy smell and unpleasant taste when drinking
alcoholic beverage while chewing dried cuttleﬁsh.
(Labeled magnitude scale, mean value ± the standard error (n = 18))
Fishy smells and unpleasant tastes such as bitterness and harshnesscaused by combining a beverage with dried cuttleﬁsh will be lower withsake than with wine.

11

The Storyof Sake

Enjoying sakeWe also researched the relationship between the color ofsake bottles and the eﬀects of light.There are many kinds oflight with diﬀerent wavelengths. Humans can see light in the
wavelengths from violet (approximately 380nm) to red (up to
780nm). Ultraviolet (UV) at wavelengths of 400nm or lower
causes chemical reactions of some ingredients in sake.
The graph below shows the light-transmission characteristics
of diﬀerent color glass bottles.Brown bottles do not transmit
l ig ht wave s b elow t he 45 0 n m r a nge t h at i nclude s U V.
Transparent (clear) bottles, blue bottles, and moss green
b o t t l e s d o t r a n s m i t U V l i g h t . H o w e v e r, c a n s a n dpaper-packaging do not transmit almost any UV light so that
their contents are not aﬀected by light.Lots of sake and beer
are sold in brown bottles because they do not transmit UV
rays.
On the other hand, high temperature causes the initiation ofa browning reaction called the Maillard reaction in sake that
contains a lot of sugar and amino acids; this reaction causes
c o l o r c h a n g e s a n d a s we e t a n d to a s te d s m e l l . H i g h e rtemperature enhances other reactions, and cause earlier
deterioration.
100
90

70
60
50

From ancient times, it has been
said that alcoholic beverage is thebest of all medicines, and it has been
believed that drinking appropriate
1amounts will contribute tomaintaining good healt h.On t heAppropriate
amountother hand, imbibing large amount
Alcohol intake
of alcohol can be hazardous as it
J-curve eﬀect
factor s i nto t he development ofvarious diseases, such as liver damage, cancer, and brain
dysfunction.A variety of investigations are being carried out
concerning drinking and health. There has been a report thatfound that people who drink alcoholic beverage in appropriate
amounts have a lower death rate than those who do not drink
at all and also lower than those who drink too much. The
graph showing the amount of alcohol consumed relative to thedeath rate is known as the J-curve eﬀect from the shape of thecurve.However, this J-curve eﬀect had not been tested byphysiological exper imentation, and there was no clear
scientiﬁc basis for it.
Therefore, we performed an experiment in which it gavesmall amounts of alcohol to animals, and investigated theeﬀects on their health to verify the J-curve eﬀect.Mice andrats who received low concentrations (1%) of alcohol wereresistant to aging, as shown in the graphs below, and were not
likely to suﬀer liver damage.These experiments suggested thata small amount of alcohol intake can be good for health. On
the other hand, as the shape of the J-curve shows, excessive
intake of alcohol is a factor disposing people to various
diseases.Therefore, please remember that a “small amount of
alcohol” is good for health is not the same as alcohol is goodfor health.Also, note that this result does not mean that
non-drinkers should be forced to drink alcohol.

40
1.2

20
10
0
200

250
White

300

350

Blue

400
Green

450 500
Brown

550 600
Moss green

650 700

750

Deep moss green

800

nm

Transmitted light spectrum of colored bottles

Sake is made by means of the established technique that has
been developed by sake brewers. It is delivered to customers at
t he hig h level of qualit y t hat sake-dr in kers ex pect. T hebackground of sake technology has been elucidated by research
institutions, including ours.If you associated sake with its
f r u it ion of m a ny ye a r s of scie nt i ﬁ c a nd te ch nolo g ic a ldevelopment, you could ﬁnd a much more distinguished tasteof sake than you ever experienced.

50

1

ALT（U/L）30

Senescence score

Transmissivity（％）

80

Alcohol and the J-curve eﬀect
Relative risk of death

The odor that comes from exposure to light is referred to aslight struck smell (nikko-shu). It should be noticed that not only
su n lig ht, but also ﬂuorescent lig hts, ca n cause slow
deterioration of sake.

0.8
0.6
0.4
0.2

40
30
20
10

0

0
26 weeks of age

27 weeks of age

Senescence-accelerated mice
Water

High-fat diet fed rat
1% alcohol

2% alcohol

Relationship between alcohol intake and senescence scores (left),alcohol intake and ALT (Alanine Aminotransferase) (right)
The graph on the left shows that the senescence scores for mice given 1% alcohol werelower than those of the other groups (the plain water-fed group and the 2% alcohol-fed
group). In the rat study results, shown on the right, the rat group fed a high-fat diet had lessincrease of the enzyme ALT (indicating reduced liver function) when the rats were given
1% alcohol than the other groups of rats did. Both studies seem to indicate that a small
amount of alcohol is beneﬁcial.

This research was conducted jointly by our institute, Hiroshima University,and the Brewers Association of Japan.

National ResearchInstitute of Brewing

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August 202212