What is koji?”

In the Lectur1, I explained that “it is koji that makes the gasoline.” 
This time I would like to explain further on the subject of “what is koji?”

“Koji” is a mold artificially propagated on steamed rice by sprinkling koji fungus on it.
The propagated fungus becomes “a clot of enzymes.” 

Then the question is, “what is an enzyme?” 
In fact we human beings have had many enzymes in us since we were born.
One typical example is the digestive enzymes contained in saliva.

Food is crunched, chewed, and broken down further due to the action of enzymes
so that it can easily be absorbed into the body.

   Note: The human body already has over 3,000 kinds of enzymes at birth.



The enzymes that make up koji fungus in the sake making process include the following.
The first one is an enzyme that breaks up rice (liquefying amylase).

The broken up rice is merely starch.
So the second one is the enzyme that converts the starch into glucose (diastatic enzyme).

For instance, the stronger the enzyme that breaks up rice is, the better the rice breaks up
and the better the taste becomes (breaking up too finely is not good, though…)
On the other hand, if the enzyme that converts the starch into glucose is weak,
again using the analogy of a car, won’t be able to reach its destination.

“The kind of sake you want to make”
must be planned and designed first to create an entire image of the sake making process.
Then the “balance” and “power degree” of the koji enzyme is designed for production.


The raw material for sake comes from grains, but the image we picture on the finished product is a “ripened fruit.” 
To achieve this, we work hard to “make koji” (gasoline production) as close as possible to this image using rice as the raw material.

Then specifically, “how do we make koji?”

 @First, rice grains are milled.

 AWash rice to let it absorb some water, then steam.

 BPlace the steamed rice in a room where the temperature and humidity is controlled.
   There, let the koji fungus settle on the steamed rice.
   The temperature is kept at 30 degree Celsius.

 CTo let the fungus settle, leave the steamed rice in a temperature and humidity
   controlled room without doing anything else for the first 24 hours.

   After 24 hours, the room temperature which began at 30 degrees goes up to around
   36 degrees.


DFrom this step, the koji making process continues until the temperature goes up to 43
  degrees over a period of 30 hours. The temperature and the time taken affects the
   “ratio of the enzymes made” during this process. In the process of settling the fungus,
  the enzyme ratio will be different with a room temperature becoming 38 degrees over
  35 hours, for instance, or 38 degrees over 40 hours. We make the enzymes over a period
  of 50 hours. Other brewers may take 55 hours or even 60 hours.

EGoing back to the story of koji, “how koji is made” differs by company.
  This is what differs the quantity and quality of the generated gasoline, eventually affecting
  the differences in taste and fragrance.

In the case of wine, as grape cultivation directly means glucose, I assume there are various
regulations on varieties and cultivations. So I believe “soil making” (terroir in French)
becomes significant.

The above chart shows how koji is made. As koji is made differently by different companies, the balance of enzymes in koji will be different, and thereby
the generated gasoline as well. And differently reached goals will make the taste and fragrance different.

Basic premises and summary

As in the wine’s “cepage,” many varieties of rice suited to making sake have been designated.
Even the same rice variety may turn out to be different depending on the milling percentage
of the rice grains. Therefore the resulting koji differs according to the rice varieties and milling
percentages. This decides the end product. So in the end, sake is all about rice (cepage) and
soil (terroir). We cannot control the yearly climate.

A difference from wine is that the skill to make a very small amount of koji is necessary in
sake making. However, in food products that go into our mouths, the potential of raw
materials cannot be changed by human hands. Attempts to change them artificially are apt
to cause some defects.


History of koji

I heard that “koji, one of the first traditional Japanese food products,” was brought to Japan by Japanese envoys to Tang dynasty China (Koji appears in documents
written around 700). The right side part of the kanji character meaning “sugar (Tou)” is the character for “Tang.”  Kanji tell a lot of stories and I believe this to be
true. To my knowledge, before this time, Kokuga (enzymes in the buds germinated from various grains) was used instead of koji. The strongest enzyme among
grain germs is malt. Malt is still in use even today (beer).

It may seem a pity that koji did not originate in Japan but was brought from China. However, “Japanese koji is in actuality very different.” 
“Why?”  “Because it has been brought down to present day having gone through its own evolution in the affects of the Japanese people’s ethnicity and climate.” 
So we should be proud of Japanese koji. “Products derived from koji or traditional fermented foods are Japanese traditional foods.” 
Since ancient times, foods have traveled across the oceans and entered different countries. But how they are used depends on the “people” of that land.

* Chinese koji-making by the way, does not wash rice grains, and directly processes raw rice grains into koji.
 In Japan, rice grains are “milled, washed and steamed.”  The process must have changed over the course of a long period of time.
 I believe that it is ethnicity that affected the development.

* Beer was born around the same period as wine in Mesopotamia.
 This means that humans were using malt already at that time. The power of enzymes was being used in ancient times also in the western world.