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3.4 Preparation of Seed Mash Used for Ricewine Brewing
The seed mash (or called starter) for rice wine brewing is called
"Jiu Mu", meaning "Mother of rice wine" ( or Mother Culture), and is
partly analogus to yeast inoculum in beer brewing.
The various seed mashes used for rice wine brewing can be
classfied into three types according to the preparation processes:
"Traditional seed mash" ("LING FANG Jiu Mu" in Chinese pronunciation) ,
"Pure Cultured Seed Mash" and Active Instant Dried Yeast (AIDY).
Traditionally, the seed mash was from the fermenting young mash. In
Song Dynasty, preparation of seed mash became a special process
before the step of rice wine fermentation. The flowchart of preparation
of seed mash described in << Beishang Jiujing>> ( published in about
the begining of 12th century) is summrized as follows:
Steeping in hot and acidified liquid
Spreading the steamed rice to cool it to a room temperature
Mixed with Jiu Qu, acidified liquid, young mash or dried seed mash
Fermentation for about 7 days
Seed mash ready for rice wine brewing
So the seed mash preparation process had no considerable difference
with main mash fermentation process.
Generally, the processes for seed mash preparation is similar to
rice wine fermentation. The particular features in seed mash
preparation are using acidified liquid to adjust pH of fermenting mash,
and the steamed rice is cooled by drenching fresh water through it.
Nowdays, some riec wine breweries are still prepareing the traditional
seed mash in modified processes which can be summerized as follows:
Fresh water Polished rice
©À©¤©¤©¤©¤©¤©¤©¤¡ú Cooling the steamed rice
©¦ ¡ý by drenching fresh water through it
©¦ Mixed with Xiao Qu ¡û Xiao Qu
©¸©¤©¤©¤©¤©¤©¤¡ú Mixed with wheat Jiu Qu and water ¡û wheat Jiu Qu
The basic ingredients required to make a batch (a vat as a unit) of
seed mash are given below:
Traditionally, the fermenting vessels were ceramic vats. Before
being used, the ceramic vats should be exposed to the sunshining first, then,
washed in lime water, finally washed in boiled water. When the
temperature of steamed rice has droped to 27-30 ¡æ, a half of the XIAO
QU powder was scattered over the rice. With a spade, the master mix
the rice thoroughly untill the Xiao Qu powder was evenly distributed.
After several minutes, a part of Xiao Qu powder was mixed in it and the
remaining Xiao Qu powder was sprinkled on the surface of the seed mash.
The central surface of the mash is indented to form a hollow oval
pattern which has a larger exposing area to the air. In this way, heat
generated during the period of fermentation is easily sent out, and
much oxygen can be utilized by the microorganisms on the surface of
the seed mash.
| ingredients || weight ( kg) |
| Glutinous rice || 125 |
| Wheat Jiu Qu || 19.5|
| Xiao Qu || 0.187~0.25
|| ( major microbes are Rhizopus spp. and yeasts)|
| Water (including the water || 230|
| absorbed in the cource of steeping|
| and steaming) |
During the cource of saccharification, it is required to control
the temperature of the mash at suitable level according to the wether
condition. The Rhizopus spp. and yeasts exsiting in the Xiao Qu begin
to multiply rapidly . Enzymes such as amylase and glucoamylase are
excreted which hydrolyze the gelatinied starch to fermentable sugar.
Usually, it takes 36-48 hours partly to hydrolyze the starch to a
suitable extent, and sweet liquid will fiil the hollow part of the
mash. The Rhizopus spp. has the ability of producing organic acids
such as lactic acid and fumaric acid which lower down the pH of the
mash. This favours the growth of yeasts and disencourages the growth of
unwanted microorganisms, yeasts ferment reducing sugars to ethanol.
When the sweet liquid has reached to a hieght of about four fifths of
the seed mash, wheat Jiu Qu and fresh water can be added to the
fermenting mash, then the mash being stirred throughly with wooden rack.
Fresh air is incorporated to nourish the growing yeasts and JIU QU
molds, carbon dioxide is expelled, and the mash from the vat's center
is mixed with the cooler portions from the sides and bottom. When all
the mash has been turned, its surface is smoothed and recovered. The
vats covered with weaved straw mats is kept at a constant temperature.
Yeasts multiply rapidly further after stirring.Stirring is repeated
three times more, and keeping the temperature of the seed mash between
26-30 ¡æ. The stirring operation is the most important one that is
always undertaken by experienced brewmasters. They judge the
fermentation situation through smelling the odour, tasting the flavour,
touching the seed mash and listening the sound from the fermenting
mash. From the comprehensive information derived from a series of
sensory evalution, they decide if it is the right time to stir the
Saccharification and fermentation of the seed mash lasts about 7
days, then the young seed mash is poured into jars with narrow neck for
secondary fermentation. Much ethanol is produced after 20- 30 days
(or may be three months ). Usually the ethanol content of the seed mash
can reached up to 15%. The chemical compositions of the seed mash is
given in table 1 below.
Table 1 The Chemical Compositions of the Seed Mash
The seed mash can also be drunk after being pressed, and this
product is called new rice wine. The seed mash manufactured with
Xiao Qu as saccharifying and fermenting agents can directly
be comsumed after 2-3 day's fermentation, and this product is called
JIUNIANG which is a sweet/sour alcoholic paste with a special flavour
and aroma. With continued incubation the product becomes more liquid.
| Ethanol (v/v, %) || 15.44 |
| Total acids ( g/100 ml) || 0.3799 |
| Sugar ( g/100 ml, glucose) || 0.3936 |
| Starch ( g/100 ml) || 4.42 |
| pH || 3.9
The advanced techniques have been used in prepration of seed mash.
These methods based on pure culture of yeast. One of these is called
"Instant Seed Mash ", Scientists have isolated a few strains of
yeasts from traditional seed mash and fermenting mash. These yeasts
are taxonomically classified as members of the Saccharomyces
cerevisiae group. The yeasts used for rice wine- making are
characterized by the high concentration of sugar and ethanol tolerance.
Although some wild yeast may be occur in wheat Jiu Qu and Xiao Qu,
which are still absolutely necessary in rice wine fermentation, the
dominant pure yeast cultures played a decisive part in rice wine
brewing. These strains produce at least 15% (v/v) of ethanol in a
fermenting mash containing 30 % (w/v) of starch.
The instant seed mash is inoculated with yeast pure cultures
instead of traditional Jiu Qu ( wheat Jiu Qu and XIAO QU) , so the
possibility of infection caused by inaseptic operation by using XIAO
QU is greatly reduced. Also, to adjust the pH of the seed mash to
around 4.0-4.5, the lactic acid is added into the seed mash instead of
adding acidified steeping water in which some unwanted microorganisms
In current practice, a large yeast inoculum is prepared from the
nutrient agar slant by a stepwise propagation of the yeast in
successively larger volumes until an adequate inoculum is available to
inoculate a plant fermenter. The basic ingredients for preparation of
instant seed mash are similar to that of traditional seed mash, but
water content may be higher than that of traditional seed mash. In
order to suppress the proliferation of indigenous lactic acid bacteriua,
lactic acid is added to the mash to regulate the pH of the mash to
about 4.0, which favorate the yeast proliferation. Usually, a 1- 2 %
(v/v) yeast inoculum is used, and the initial temperature of the mash
is set at 26-30 ¡æ according to the weather. When the temperature of
the mash reaches above 31-32 ¡æ, stir the mash with pressed air. The
cultivation time lasts about 1-2 days.
Another method of pure culture of yeast is currently used in rice
wine breweries. Glucoamylse is added to the mash ( the ingredients are
almost the same as those in the traditional seed mash but diluted with
much water), then raise the temperature of the mash to 55- 60¡æ.
Glucoamylase converts the geletinized starch in order to reduce sugar
which is easily used by yeast culture. At this high temperature, wild
yeasts and bacteria are destroied, so pure yeast cultures grow well.
The Active Instant Dried Yeasts ( AIDY) developed specially for
rice wine brewing have been commercially produced in a large scale.
The application of this type of yeast culture is widely accepted in a
number of rice wine breweries.
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