Basic HTML Version
Rice
The rice used for brewing sake is
called shuzō kōtekimai (sake rice).
The grain is larger, stronger, and
contains less protein and lipid than the
ordinary rice eaten by the Japanese.
The rice has a starch component
called shinpaku in the center of the
grains. Since sake made from rice
containing only starch has a superior
taste, the rice is polished to remove
the bran. If a grain is small or weak, it
will break in the process of polishing.
This rice is used only for making sake,
because it is unpalatable for eating.
Water
Water is one of the important ingredi-
ents for making sake. It is involved in
almost every major process of sake
brewing from washing the rice to dilu-
tion of the final product before bottling.
Mineral content can play a large role
in the final product. Iron will bond with
an amino acid produced by the koji
to produce off flavors and a yellowish
color. Manganese, when exposed to
ultraviolet light, will also contribute to
discoloration. Conversely potassium,
magnesium, and phosphoric acid
serve as nutrients for yeast during
fermentation and are considered desir-
able. Yeast will use those nutrients
to work faster and multiply resulting
in more sugar being converted into
alcohol.
Brewing
Moromi, the main mash Sake is pro-
duced by the multiple parallel fermen-
tation of rice. The rice is first polished
to remove the protein and oils from
the exterior of the rice grains, leaving
behind starch. Thorough milling leads
to fewer congeners and generally a
more desirable product.
Newly polished rice is allowed to
“rest” until it has absorbed enough
moisture from the air so that it will not
crack when immersed in water. After
this resting period, the rice is washed
clean of the rice powder produced dur-
ing milling and then steeped in water.
The length of time depends on the
degree to which the rice was polished,
ranging from several hours or even
Production
overnight for an ordinary milling to just
minutes for highly polished rice.
After soaking, the rice is steamed on a
conveyor belt. The degree of cooking
must be carefully controlled; over-
cooked rice will ferment too quickly
for flavors to develop well and under-
cooked rice will only ferment on the
outside.
The microorganism Aspergillus
Oryzae (a mold) is sprinkled onto the
steamed rice and allowed to ferment
for 5–7 days. After this initial fermen-
tation period, water and the yeast
culture Saccharomyces Cerevisiae
are added to the koji (rice and mold
mixture) and allowed to incubate at
4 degree Celsius for about 7 days.
Over the next four days, pre-incubated
mixture of steamed rice (90 kg), fer-
mented rice (90 kg) and water (440L)
are added to the fermented mixture in
three series.
The main mash then ferments, at
approximately 15-20 degree Celsius
for 2–3 weeks. With high-grade sake,
fermentation is deliberately slowed by
lowering the temperature to 10 °C (50
°F) or less. Unlike malt for beer, rice
for sake does not contain the amyl-
ase necessary for converting starch
to sugar and so it must undergo a
process of multiple fermentation. The
addition of A. Oryzae provides the
necessary amylases, glucoamylases,
and proteases to hydrolyze the nutri-
ents of the rice to support the growth
of the yeast (S.cerevisiae).
After fermentation, sake is extracted
from the solid mixtures through a filtra-
tion process. For some types of sake,
a small amount of distilled alcohol,
called brewer’s alcohol, is added be-
fore pressing in order to extract flavors
and aromas that would otherwise
remain behind in the solids. In cheap
sake, a large amount of brewer’s
alcohol might be added to increase
the volume of sake produced. Next,
the remaining lees (a fine sediment)
are removed, and the sake is carbon
filtered and pasteurized. The sake is
allowed to rest and mature and then
usually diluted with water to lower the
alcohol content from around 20% to
15% or so, before finally being bottled.
Maturation
The process during which the sake
grows into a quality product during
storage is called the maturation or
maturing process. Mature sake has
reached its ideal point of growth. New
sake is not liked because of its rough
taste, whereas mature sake is mild,
smooth and rich. However, if it is too
mature, it also develops a rough taste.
Nine to twelve months are required
for sake to mature. Aging is caused
by physical and chemical factors such
as oxygen supply, the broad applica-
tion of external heat, nitrogen oxides,
aldehydes and amino acids, among
other unknown factors. It is said that
Saussureae radix from the Japan
cedar material of a barrel containing
maturing sake comes to be valued,
so the barrel is
considered
indispensable.