The Storyof Shochu

NRIB(National
Research Instituteof Brewing)
December 2021

FeaturedarticleShochu 1(Summary)1compounds. You can enjoy the full ﬂavor and mellow tasteof shochu.

How to enjoy shochu
How to make shochu
Flavor characteristics based on main ingredients
Geographical Indication

1
2
6
8

Shochu is a distilled alcoholic beverage unique toJapan. Unlike wine, beer or sake, the shochu making
method includes a distillation process like whisky andgin making. Based on the diﬀerence in the distillation
process, shochu is classiﬁed as either pot distillation
shochu or continuous distillation shochu.
Pot distillation shochu
Pot distillation shochu (simple system distillation
Japanese spirits) is a traditional type of Japanese spirit
made from various ingredients such as rice, barley, or
sweet potato. Honkaku shochu (authentic shochu) andawamori are included in this category. The resulting
fermented mash is distilled using a pot still. And it has
an alcoholic content of 45% alcohol by volume (ABV)or less.
Continuous distillation shochu
C o n t i n u o u s d i s t i l l a t i o n s h o c h u (c o n t i n u o u s
distillation Japanese spirits) is spirit made from a
fer mente d m a s h t h at h a s b e en d i s t i l le d i n acontinuous/column still. It has an alcoholic content ofunder 36% ABV.

Mizuwari（shochu with cold water）
Put several pieces of ice into a
gla ss ﬁ rst. Then, pour a s much
shochu as you d like, and top up
with water. After lightly stirring,cold and refreshing shochu with asmooth ﬂavor proﬁle is ready to beenjoyed. A mix of around 10-15%
ABV is recommended. For mixing
ratio, the ﬁgure below left (Alcohol
content and temperature) may be
useful.
Straight or on the rocks
To fully enjoy t he ﬂavor of shochu, dr in k ing its t ra ig ht or on t he ro c k s i s re com mende d . A f ter
enjoying the aroma of shochu from the glass, sip a
sma ll a mount (1-2 m L) of shochu a nd ta ste it byspreading it over your tongue. Drinking water as achaser is also recommended.
Shochu with soda/ shochu-based cocktail
Sho chu w it h so da i s a not her
choice to enjoy a refreshing styleof shochu. Recently, several kindsof sho chu-ba sed co ck t a i l havebeen created.

How to enjoy shochu
How to drink
Oyuwari（shochu with
hot water）
The ratio of hot water
to shochu is generally
4:6, 5:5, or 6:4. Shochu iswarmed by this dilution,a nd it en h a nc e s t heevaporation of aroma

Alcohol content and temperature
10％
60℃
(140°
F)

12.5％
50℃
(122°
F)

95°
C (203°F)of hot water

5

4

Shochu of 25%
alcohol content

5

6

6

4

15％
40℃
(104°
F)

Shochu and food pairing

Generally, the ﬂavor of shochu is not so strong andgoes well w it h ma ny kinds of food. For insta nce,
shochu refreshes your mouth after eating greasy food.
Therefore, shochu is enjoyed with food like wine and
sake.

01

Yeast

How to make shochu
Ho
Pot distillation shochu

The typical method for making pot distillation
shochu is as follows:
1. Koji making
Koji is a culture of a special kind of fungi,
called koji mold, on grains. Koji is used tob re a k t he s t a rc h c ont a i ne d i n t he m a i n
ingredient into sugars.
2. Starter culture
To g row yeast for fer mentation, a sta r ter
culture is prepared with koji, water, and asmall amount of yeast.
3. Main fermentation mash
The main ingredient is added to the starter
culture, and fermentation continues.
4. Distillation
The fermented main mash is put into a pot
still for distillation, and shochu is made.
5. Storage and shipment

Yeast

Ingredients
Koji

Koji
ingredients

Koji

The role of koji
Koji produces many kinds of enzymes. Theseen z y mes brea k dow n sta rch i nto suga rs . Th isprocess is called sacchariﬁcation. Since yeast can tferment starch, the starch in the main ingredients(rice, barley, sweet potato and others) has to bes a c c h a r i ﬁ e d i nto s uga r ﬁ r s t , a n d t he n ye a s t
ferments it into alcohol.
In case of beer and whisky, enzymes produced byma lt play t he role of s accha r i ﬁc at ion a nd
fermentation follows as another separate process.
I n t he c a s e of s ho c hu , where koji i s us e d forsaccha r i ﬁcat ion, bot h saccha r i ﬁcat ion a nd
fermentation simultaneously take place in the same
vessel.
Another role of koji is the production of citricacid, which keeps the starter culture and main
fermentation mash acidic. This role is explained in
the next section (The varieties of koji mold).

Starter culture

StarchKoji
enzymes

Main ingredients

Sugar

Yeast
AlcoholFirst addition
Main fermentation mash

Sacchariﬁcation

Fermentation

Second addition
Distillation
Storage and shipment
Pot distillation shochu on the market

Ingredients

Koji is made with rice in many cases, and insome cases with barley or other ingredients. For themain fermentation mash, various main ingredients
including cereal grains, sweet potatoes, and so on
may be used. Shochu is na med a fter t he ma iningredient. For example, shochu made from sweet
potatoes in the main fermentation mash is called
sweet potato shochu even if rice is used for its
koji ma k i ng. It s i mpor ta nt to note t hat ma i n
ingredients are steamed before koji making andfermentation.

02

Starter culture

Water

Sacchariﬁcation and fermentation in main fermentation
mash of shochu

Overview of shochu making process

Koji ingredients

Koji

Main ingredients

The varieties of koji moldThree varieties of koji mold are used for shochu
making: (1) black, (2) white, and (3) yellow koji
mold.
Black a nd wh ite koji molds a re i n t he sa me
category of fungi and have mainly been used forshochu making since the beginning of the 20th
century.
On the other hand, yellow koji mold has longb e e n u s e d fo r s a ke m a k i n g , a nd it wa s u s e dextensively to make shochu as well up until about
10 0 ye a r s ago. I n re c ent ye a r s , s ome s ho c hu
distilleries are once again using yellow koji moldwith the aim to diversify their range of products.

One of the main reasons to
use black a nd wh ite kojimolds for shochu making istheir high production of citricacid. Thanks to citric acid,the starter culture and main
fermentation mash of shochua re kept acidic, wh ich iseffective to avoid
contamination by undesired
microbes. This is an
important point when making
shochu in the southern andw a r m e r r eg io n s of Ja p a n ,such as Okinawa Prefecture
and Kyushu Island.

The Storyof Shochu

Main fermentation mash

Water
Koji

Citricacidity

Citric acid makes
fermenting mash
acidic to avoid
contamination by
undesired microbes.

Koji making
Koji is made with rice in many cases, and insome cases with barley or other ingredients. In
case of r ice koji making, r ice grains are ﬁrstly
washed and steeped in water before steamed andcooled down to desired temperature. Then the kojimold spores are spr inkled over the grains andmixed well. The mixed grains are kept at 40-42°C(10 4 -10 8°F ) to g row koji mold , a nd t hen t hetemperature is lowered to 30-35°C (86-95°F). This
lower temperat ure is necessa r y to i nduce t heproduction of citric acid. This process takes about 2
days.

Starter culture: To grow yeast

For the starter culture, koji, water, and a small
a mount of yea st a re m i xed i nto a ta n k or
earthenware jar. The starch contained in the koji
ingredients is sacchariﬁed by koji enzymes, and theresulting sugars are consumed by yeast throughfermentation. The citric acid in the koji prevents thegrowth of contaminating microbes, whereas yeast
is resistant to acidic conditions. This fermentation
continues for 3 -8 days at around 30°C (86°F),
allowing the yeast to thrive. This process is known
as the starter culture.

Main fermentation mash:
Sacchariﬁcation and fermentation
The main ingredient is steamed, cooled down,
and added to the star ter culture together withwater. Then, sacchariﬁcation and fermentation takeplace i n t he ma sh . It s ma x i mu m temp erat u rereaches 28-32°C (82-90°F), and fermentation lasts
around two weeks. The ﬁnal alcohol content of themain fermentation mash is approximately 14-20%.
Preparation of fermentation mash
Koji

Yeast

Water

Yeast is cultivatedfor mainfermentation mash.

Rotating drum for koji making: This type of machine is
widely used in shochu distilleries.
３〜８ days later

Main ingredients

Starter culture

Water

2 weeks later

To distillation

The varieties of koji mold(from left: black, white, and yellow koji mold)
Rice is washed in this rotating drum. On the next day,rice is steamed and the koji making process takes place
inside the drum under controlled temperature.

Main fermentation mash

The aromacomponent isformed together
with alcohol by the
yeast.

03

Distillation

Skimming
Storage

Filtration

Shipment

Ingredients

Fermentation

Distillation

Shipment

How to make shochu
Ho
Distillation

After fermentation, the main mash is distilled.
Alcohol and various volatile aroma compounds, aswell as water, are isolated from the main mash, andshochu is made. Thus, the distillation process turns
the mash into a spirit .
The fermented main mash is transferred to a pot
still and heated. As the temperature of the mash
rises, alcohol and other volatile compounds begin
to evaporate. The vapor is cooled down while itpasses through the concentration column, lynearm, and cooling condenser, and it is collected as
distillate. Various volatile compounds are separated
and condensed due to the diﬀerences in boilingtemperature or volatility. For example, the boilingtemperature of water is around 100°C (212°F),
while that of alcohol is around 78°C (172°F). Thus,
alcohol vaporizes at a lower temperature and isconcentrated through distillation. The alcohol
concentration in the main mash is around 14-20%,
and it is 37-43% in the distilled shochu.
Most whisky goes t h rough t wo or more
distillation cycles. In contrast, most pot distillation
shochu is dist il led on ly once i n a pot st il l.
Therefore , s ho c hu c ont a i n s va r iou s ﬂ avor
compounds derived from the mash, which make up
the characters of individual shochu brands.

Atmospheric distillation
At mospher ic dist illat ion is per for med underatmospheric pressure. The main mash is boiled atso high temperature that most of components easilytransfer to the distillate. In addition, chemical
reactions such as decomposition and synthesis are
en ha nced at a h igher temperature. Thus, newcompounds are generated during the distillation
process, and some of them are transferred to the
distillate. Therefore, shochu made with atmosphericdistillation features full ﬂavors and richness.
Vacuum distillation
It is performed with reduced pressure inside thepot. At a lower ba romet r ic pressure, a s at t hesummit of a high mountain, liquid boils at a lower
temperature. Thus, by using vacuum distillation the
shochu contains fewer ﬂavor compounds, and only
those that evaporate easily (e.g. esters) escape fromthe still along with alcohol and water. Therefore,
vac uu m - d i st i l le d s ho chu h a s l ig hter ﬂ avor
compared to atmospheric-distilled shochu.
The diﬀerence between atmospheric distillation andvacuum distillation
Vacuumpump

Pot still (left) and overview of distillation (right)
Lyne arm

Vapor turns to liquid
after cooling.

85-95°
C(185-203°
F)

Storage, shipment

Freshly-distilled honkaku shochu and awamori
usually have a slightly pungent odor and a coarse
and tingly sensation on the tongue. Also, they
contain some oily compounds derived from theingredients. These oily compounds are likely toturn into oxidized oil with an unpleasant smell.
Thus , t he oily compounds a re removed bys k i m m i n g o r ﬁ lt r a t i o n b e fo r e s to r a ge . A l s o ,precautions against oxidation are taken duringstorage and maturation. The smell and palatabilityof freshly distilled shochu become delicate andmellow during maturation.
The a lc ohol c onc ent r at ion of s ho c hu a f ter
d i s t i l l at ion i s 37- 43% . However, it i s u s ua l ly
reduced to 20-25% with water before bottling andshipment. Generally, shochu is matured in stainlesssteel tanks, not barrels, and shipped within a year
after distillation. Thus, the maturation period ofshochu is much shorter than whisky and brandy.
One possible rea son for t his shor t maturat ion
period is that most shochu is characterized by the
ﬂavor derived from its ingredients.
Some special kinds of shochu are, of course, agedin ea r t henwa re ja rs or wooden ba r rels. Whenshochu is stored in earthenware jars for a longtime, it acquires a mellow aroma and ﬂavor due tocontact with oxygen and catalytic action via theminerals contained in the earthenware jars.

Continuous still (left) and a distillation overview (right)
Distillate

Distillation
tower

The higher the row,
the moreconcentrated thealcohol will be.

Vapor

Still plate

Steam【Stillplate structure】
Vapor Liquid

Main mash
Continuous supplyof fermentation
mash enables
eﬃcient mass
production.

The same result as redistilling in a pot still multiple times.

Vapor

Cooling
condenser

Atmospheric pot still

LiquidMain mash isheated and givesoﬀ vapor.

SteamDistillate

Distillate iscollected.

In addition to a traditional distillation method,which is carried out under normal atmosphericpressure (atmospheric distillation), a new method
has been developed, where distillation is carriedout under reduced pressure (vacuum distillation).

04

The cotinuous still was invented by Mr. Robert
Stein in Scotland in 1826 and was improved by Mr.
Aeneas Coﬀey in Ireland in 1831. This technique isused for the production of grain whisky and vodka.
It was introduced to Japan, and a new type ofs ho c hu , c ont i nuou s d i s t i l l at ion s ho c hu , wa s
launched around 190 0. Continuous distillation
shochu is often made from molasses or corn, but it
has a neutral character. It is used to make liqueurwith fruits, such as plum (umeshu), as well as forc o c k t a i l s . E ve n t houg h t hey a re b ot h c a l le dshochu in Japanese, pot distillation shochu iscompletely diﬀerent from continuous distillation
shochu due to how it is made.

45-55°
C(113-131°F)

Concentration
columnPot

Continuous distillation shochu

Vacuum pot still

Component easy to evaporate
Component hard to evaporate
Component generated by heating

E it h e r of t h e t wo m et h o d s c a n b e a p p l ie ddep end i ng on t he ch a rac ter i st ic s of t he ﬁ na l
product and consumer preferences. Some products
are produced by blending shochu made with theatmospheric method and that with the vacuum
method. In addition, an improved vacuum still
which employs intermediate pressure has beendeveloped and contributes to the diversiﬁcation ofshochu.

Classiﬁcation of pot distillation shochu
Pot distillation shochu is classiﬁed into thefollowing ﬁve categories:
1. Shochu made from some kind of grains or
tubers and roots and their koji (e.g., rice
shochu, barley shochu, or sweet potatoshochu)2. Shochu made from grain koji only (e.g.,awamori)
3. Shochu made from sake lees (sake leesshochu)4. Shochu made from brown sugar and ricekoji (brown sugar shochu)
5. Shochu made from ingredients other than
1- 4 . Fo r e x a mple , s h o c hu m a d e f r o msesame, pumpkin, or carrot can be labeledhonkaku shochu.

Honkaku shochu and awamori are classiﬁed
in t he pot distillation shochu g roup. If t heproducts implement certain standards, they are
granted to be labeled honkaku shochu orawamori. A summary is as follows.
The relationship between honkaku shochu andawamori in the category of pot distillation shochu
Pot distillation shochu
Honkaku shochu

It includes the above -mentioned list 1- 4 andpar t of 5 (ingredients approved by thecommissioner of the National Tax Agency ofJapan) and nothing is added except for water.

AwamoriPot distillation shochu made fromrice koji（only those made fromblack koji mold）and water.

05

Flavor characteristics
Flavorcharacteristics
based
based
on mainonmainingredients
ingredients
Sweet potato shochu

Sweet potato shochu has a distinctive sweet
ﬂavor, however, its ﬂavor character varies widely
depending on the type of sweet potato (and manyother factors). Sweet potato shochu is often enjoyedby dilution with hot water, cold water, or on therocks. Its distinctive ﬂavor and mild sweetness canbe enhanced by warming.

Rice shochu

The aroma of rice shochu is somewhat similar tothat of freshly cooked rice, which complements thesavory notes in food. The variety of ﬂavors ̶ fromrich ﬂavors of atmospheric distillation, ﬂowery andlight aromas of vacuum distillation to particularly
matured ﬂavors of earthenware jar- or barrel-aged
ones ̶ enables us to appreciate attractive variationin rice shochu.
R ice shochu bra nds w it h r icher ﬂavors (e.g.
atmospheric-distilled) are often enjoyed with hotwater whereas those with lighter ﬂavors or ﬂoweryaroma are usually enjoyed on the rocks.

The Storyof Shochu

Brown sugar shochu

In general, brown sugar shochu is characterized
by the sweet aroma of brown sugar with slightly
acidic a nd oily ﬂavors l i ke coconut. It s
unexpectedly light on the palate, contrary to thea roma. Brow n suga r shochu is most favorably
enjoyed by dilut ing w it h water to en ha nce its
unique ﬂavor and mellowness, or on the rocks.
Brown sugar shochu is a specialty of (and is only
a l l owe d to b e m a d e i n) t h e A m a m i I s l a n d s ,Kagoshima Prefecture.

Awamori

Sweet potato

Barley shochu

Barley shochu has a delicate and speciﬁc aroma
of barley with a mellow and sweet proﬁle. The
ﬂavor of barley shochu varies based on still types:
vacuum distillation makes it light and smooth,while atmospheric distillation makes the savory
aromas more intense and balanced with the taste.
Depending on the type of shochu, it can be servedin various manners such as with hot water or withcold water.

Awamori is a specialty of Okinawa Prefecture,and is known for its rich ﬂavor. In addition to af r u it y a rom a s i m i l a r to apple s a nd b a n a n a s ,awamori has a savory ﬂavor caused by atmosphericdistillation. Awamori contains a relatively large
amount of oily components contributing to deep
and rich ﬂavors. Furthermore, kusu, which meansaw a m o r i m a t u r e d fo r a t l e a s t 3 y e a r s a f t e r
distillation, has its own distinctive aroma similar tosweet vanilla and mellow ﬂavors.
It is recommended to drink kusu straight, however,other types of awamori are best enjoyed on therocks with water.
Indica rice (left) andJaponica rice (right):
long-grained and hard
Indica rice has been used forawamori making.

Buckwheat shochu

Buckwheat shochu has a distinctive fresh aroma
of buckwheat and a light ﬂavor. Each drinking styleoﬀers var ying savor y, pleasurable experiences:brisk aroma on the rocks, mild taste with water, ora gradually-spreading savory taste with hot water.
Recently, it has been suggested that buckwheat
shochu with soda is also worth a try. In addition, atbuckwheat noodle restaurants, shochu is sometimes
blended w it h reser ved hot water a fter boilingbuckwheat noodles to create an enjoyable drink.
BarleyBrown sugar

Sake lees shochu

Kasutori shochu, which is a traditional type ofsake lees shochu, has complex ﬂavors such as ahint of rice husk, dry grass, and the sweet aroma ofsake lees. In addition, kasutori shochu distilled using
the steaming basket method still has a hint ofwoody aroma. These distinctive ﬂavors are very
intense immediately after distillation, but the time
during storage appropriately harmonizes theseﬂavors before the shochu is sent to the market.
Kasutori shochu is usually dr unk cold or on therocks. It is also used to make plum liquor.
Another type of sake lees shochu is made fromthe mashing (kasumoromitori) method and is milder
than kasutori shochu.When sake lees from ginjo-shu
are distilled under vacuum pressure, the shochu
has a fruity aroma similar to that of ginjo-shu. Thesetypes of sake lees shochu are often enjoyed cold oron the rocks.

Shochu history
The shochu making techniques are considered
to have a r r ived i n t he Ry uk y u K i ngdom orpresent Okinawa Prefecture, Japan, from theK i n gd o m of S i a m (m o d e r n - d ay Th a i l a n d)
through the route between Southeast Asia andChina sometime during the 15th century. There
are a number of theories as to how shochu wasintroduced to Kyushu Island. Shochu is said tohave arrived from Okinawa, Korea, China, oreven Europe, but no deﬁnitive evidence supports
any of these theories.
The oldest document on shochu was writtenby the Portuguese Jorge Alvares in 1546 in his
report Aﬀairs Regarding Japan. According tothis report, rice shochu called orraqua wasdrunk in Yamagawa or currently Ibusuki City in
Kagoshima Prefecture.
The oldest record of the word shochu was
discovered on a wooden board in the rafters ofK o r i y a m a H a c h i m a n S h r i n e i n I s a C i t y,
Kagoshima Prefecture in 1559. This graﬃti
complains that The head priest is so stingy that
he never serves us a cup of shochu! Having sucha stingy head priest is a great nuisance for us.
It s clear that shochu was made in the areaaround that time. After that, shochu making
techniques were introduced into other parts of
Kyushu Island.
Although the origin of shochu production
dates back well over 40 0 years, continuous
distillation techniques are relatively
new-invented in the 19th century. Thus, the ﬁrst
domestically produced continuous distillation
shochu did not make an appearance in Japan
until after 1900. Since then, the development of
production techniques suitable for bringing out
the fragrance of the diﬀerent ingredients, thediscover y of super ior yea st st ra i n s , a nd
improvements in modern still technology haveall contributed to today s continuous distillation
shochu.
Routes of transmission for shochu making techniques
Continuous distillation(19th century)

Pot distillation
̶Kyushu Island(15‒16th century)

Pot distillation
̶the Ryukyu Kingdom(15th century)

Buckwheat
seeds

06

07

The Storyof Shochu

Geographical Indication
Details of Geographical
Indication

Geographical Indication (GI) is a system which
promotes the appropriate usage of the name of thegeographical origin, which is the common propertyof the area. This means that alcoholic beverages canclaim exclusive use of the name of the place where it
was made.
When a GI is designated to alcoholic beverages, iti ndic ates not on ly t hat t h is is f rom t he cor rect
production area but also the quality is suﬃcient tomeet certain criteria.
S o m e e x a m p l e s o f f a m o u s G I s fo r d i s t i l l e dalcoholic beverages may be Cognac and Armagnac
for brandy categories and Scotch for whisky.
In Japa n as of 2021, GI regions desig nated to
distilled alcoholic beverages (shochu) are Iki, Kuma,
Ryukyu, and Satsuma.

Iki (shochu)

Iki City (Iki Island), Nagasaki Prefecture
Iki is an internationally ap p roved p rod uc tion
district of barley shochu. Iki City is considered asa birthplace of barley shochu.

Kuma (shochu)

Kumamoto Prefecture's Kuma County and
Hitoyoshi City
Kuma is an internationally approved production
district of rice shochu.

Satsuma (shochu)

Kagoshima Prefecture (withthe exception of Amami City
and Oshima County)●

As of 2021●

Sat su ma is an internationallyapproved production district ofsweet potato shochu.
●

Ryukyu (awamori)
Okinawa Prefecture

Ryukyu is an internationally approved production
district of awamori.

08

National ResearchInstitute of Brewing

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Hiroshima, 739-0046
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December 2021