Milling & Polishing
Two types of grinding stones make fine adjustment of polishing possible
Constituents that will take away from the refined flavor of the finished product are removed from the surface of brown rice. The milling machine at the Shirakabe-gura Brewery has two built-in grinding stones of different types to carefully polish rice in two stages and prevent rice from breaking during the milling and polishing processes. |
Washing & Soaking
Exact control of absorption percentages is possible
This process is to remove rice bran and let the rice absorb water. This is an important process that determines the final quality of sake. Rice washing machines rotate gently as human hands. The soaking tanks can set water absorption time exactly. |
 |
|
A soaking tank that can precisely control the water absorption percentage
|
|
Steaming and Cooling
Good steamed rice makes good koji and yeast starter
Rice is steamed until it is “just right” with rice steamers that reproduce the principle of a traditional Japanese rice cooker. While gently raveling out steamed rice, a cooling machine cools the rice to the appropriate temperatures for kakemai and kojimai using warm air, open air or cold air flows. |
Koji Making
Most important process in sake brewing
It is said that quality of sake is determined firstly by koji, or steamed rice with koji mold spores, secondly by moto, or the process of growing the starter, and thirdly by the brewing method. The koji- making process has a decisive influence on the final quality of sake. With koji-making machines that reproduce the principle of the traditional huta-koji method, koji is nurtured at an appropriate temperature and humidity level. |
 |
|
The growth of koji is checked by personnel. They touch it with hands, smell it and put it in their mouths. Koji has chestnut-like aroma and is slightly sweet.
|
|
Moto (starter making)
The brewery also engages in a traditional Ki-moto starter-making process that requires proficient skills
Koji, steamed rice and water are mixed to nurture yeast. The Shirakabe-gura Brewery engages not only in ordinary quick-brewing type methods but also adopts the Ki-moto process, represented by the yamahai-moto method. |
Moromi (main mash) making
Bubbles in moromi are observed daily to manage fermentation
Yeast starter, koji, steamed rice and water are poured in a tank for fermentation. For this process, which takes more than 30 days, temperature control is of utmost importance. According to the progress of fermentation, the temperature of moromi is adjusted little by little. The brewery’s original beaters are used as fermentation tanks to mix the entire moromi evenly without smashing the grains of rice to keep the temperature of the moromi even. |
 |
Pressing
Slow pressing using old-style pressing techniques
With an automatic pressing machine, pressure is applied gently to the moromi to separate it into fresh sake and sake cake. At the Shirakabe-gura Brewery, the moromi is pressed by the weight of piled-up sake bags, or a method known as hukuro-tsuri is conducted where bags of sake are hung to let the raw sake run through. |
Aging
Quality is checked by brewers using their five senses
After filtration and pasteurization, the raw sake is stored and aged to produce a balanced, mellow taste. Finally, after componential analysis and sensory tests, the sake is bottled. |
|
