Prediction of brewing characteristics from one gram of brown rice
In sake making, sake rice greatly influences sake quality. It is, therefore,
important to know the brewing characteristics of sake rice before sake making
season. So that, the quality design and brewing process for sake can be adjusted.
Many studies have been conducted on the brewing characteristics of sake rice;
however, such analysis is time consuming. Therefore, we developed a method
for predicting many brewing characteristics of sake rice using a small amount ofbrown rice within a short period. In this method, low molecular weightcompounds were extracted from brown rice and then the amounts of individualcompounds were determined. The 29 brewing characteristics were predictedfrom the extracted low molecular compound. The predicted brewing
characteristic include not only those of sake rice itself, such as its digestibility
and crude protein content, but also those related to enzymatic activities duringkoji production under certain conditions and the fermentation process and thesake aroma components (patent pending). In the test conducted in the fiscal year
2018, when the harvest of sake rice was delayed by over two weeks comparedwith the average year, 85 samples of sake rice were tested before January in thenext year, when full-scale sake brewing commenced. However, there are still
issues that obstruct the commercialization of this technique, and we are currently
addressing them.
【Glossary】

○ Brewing characteristics
During the process of sake making, sake rice is polished, soaked in water, and steamed before being subjected to koji and sakemaking. The characteristics of sake rice influence these processes, for example, rice grains may break during the rice polishingprocess, and enzyme titers may be affected during the koji making process. These influences are called brewing characteristics.

It is now possible to predict the brewing characteristics of ingredient riceusing only a small amount of brown rice. Further consideration is necessary
to put this method into practical use.

Prediction of the brewing characteristics of rice using one gram of brown rice
• Want to quickly determine the characteristics of sake rice using a very small amount of brown rice.
• Also want to know not only the analytical values for sake rice, e.g. digestibility and crude protein content, butalso the effects on the enzymatic activities of koji and the aroma components of sake, among others.

Various types of sake rice(brown rice)

Brewed& analyzed

Analytical values for sake rice and brewing
characteristics◆ Standard analysis data for sake rice
(conventional method)+Measured after brewing under certain conditions◆ Koji making data (α‐amylase activity, etc.)◆ Brewing properties data (reduced CO2, etc.)◆ Sake component data (aroma components, acidity,etc.)

Objective variables (54 items)
Prediction

Now possible to predict 29 brewing characteristics using less than one gram of brown rice
Predictable items: analytical values for sake rice (digestibility, crude protein content, potassium content, etc.), enzymatic
activities of koji (glucoamylase activity when koji is made from 50% white rice, etc.), fermentation characteristics (sakelees ratio, etc.), sake components (ethanol content, ethyl caproate, etc.)