The Winery Oura of Nagano-ken

Discovering the wine region of Nagano-ken

Junmai (pure sake) literally translates to "pure rice". It is a high-quality class of sake, a rice-based Alcoholic beverage that is an intricate Part of Japanese culture. In order to be classified as Junmai sake, the beverage must be made with only rice, water, and koji, the mold that triggers Fermentation. Sake can be found in a variety of types and styles, each with its own Organoleptic properties.

Like wine, sake can taste different depending on the origin of rice used, where it was produced, the degree of rice polishing, the water source, the brewing process as well as how the sake is filtered post-fermentation. To make Junmai sake, the polished rice is cooked, and then mixed with Yeast">yeast and koji, a filamentous fungus . The koji converts the starch in rice to fermentable sugar, while the yeast simultaneously converts the sugar into alcohol. This process of multiple parallel fermentations is Complex: if the koji doesn't convert the rice to sugar quickly enough, the yeast will die, and conversely, if there is too much sugar at once, it overpowers the yeast and stops fermentation.

Over the course of about a month, more rice, koji and water is added to the mixture until the sake finishes fermenting. Since the process of multiple parallel fermentations can leave alcohol levels of 20 percent or higher, water is usually added to achieve the desired alcohol level. Before 2003, Japanese law stipulated that the rice must be polished down to below 70 percent of its original mass, a process called Seimai Buai. The process is done to remove the bran, creating a purer form of sake.