About Junmai Sake

What is Junmai Sake?

There are two main types of sake. Junmai sake is made with rice and water alone, while honjozo/futsuu sakes are made by adding brewing alcohol to the rice and water. Nakamoto Sake Brewery exclusively makes junmai sake. Because the ingredients are simple, the aroma and flavor can vary greatly depending on the brewing method and the quality of the rice and water. Rice used in sake is polished before brewing. The portion of the grain that remains after polishing is represented as a percentage and called the Rice Polishing Ratio (RPR), and the category of junmai sake can be further subdivided based on the RPR.

Junmai Sake

Junmai sake is made from rice and water. It contains a large amount of lipids, which are found in the outer layers of rice grains and confer the umami and deep richness of the rice to the sake.

Junmai Ginjo Sake

Junmai ginjo sake is made from rice with an RPR of 60% or less, fermented for a long time at a low temperature according to the ginjo brewing process. More of the outer layers of the sake grains have been removed than in junmai sake, reducing the amount of zatsumi, and the ginjo brewing process produces a fruity aroma. Junmai ginjo sake is characterized by its clean, refreshing taste and well-balanced fruity aroma.

Junmai Daiginjo Sake

Junmai daiginjo sake is made with highly polished rice with an RPR of 50% or less--even less than in junmai ginjo sake--and following the ginjo brewing process. Careful polishing of the rice removes lipids and proteins that would otherwise suppress the aromas, producing a luxurious sake with no zatsumi off-tastes. Junmai daiginjo sake stands out for its cleaner flavor.

The Brewing Process

Japanese sake is a very delicate beverage, and to ensure a fine taste, brewers must work carefully at each step from the polishing of the rice to the shipping of the final product.

①Polishing, Washing, Soaking, Steaming, and Cooling the Rice

Sake is made from rice specially suited for making sake, which is different from the rice normally used for food. The outer surface of the rice is rich in proteins and other substances that can produce the unwanted off-flavors known as zatsumi. The rice is therefore polished to remove these substances. After being washed, the polished rice is soaked so that it absorbs the right amount of water for the next step in the process, steaming. Having absorbed water, the rice is loaded into a machine called a koshiki to be steamed from below. The steamed rice is removed from the koshiki while still hot and is cooled in a cooling machine with a conveyor belt.

②Making Koji

The rice is moved to a koji room where the temperature is regulated, and koji cultures are sprinkled on the rice to propagate. The substance made from the growth of the koji cultures is called "koji," and it has the function of converting the rice starch into glucose.

③Making the Shubo

Shubo literally means "sake mother" and refers to the yeast starter used when brewing sake. Yeast has the function of converting glucose into alcohol, and the brewing of sake requires large quantities of it. It is therefore cultivated by adding yeast to the mixture of water, koji, and steamed rice, and then letting it grow.


According to standard sake brewing processes, koji, steamed rice, and water are added to the shubo in three separate stages instead of all at once. Adding all of the ingredients at once and allowing them to ferment dilutes the acidity of the shubo, which increases the risk of microbial growth. In order to avoid the risk of the sake spoiling, brewers introduce the ingredients in three separate batches. This process is called sandan jikomi, which literally means, "three-stage preparation." The substance created by this careful and thorough three-stage process is called moromi.

⑤Pressing, Ori Removal, and Filtration

The moromi is pressed to separate it into sake and the sake lees. This is one of the operations where sake breweries can give their products a distinctive taste, as the amount of pressure used changes the flavor of the sake. Freshly pressed sake is cloudy with fine residues called ori suspended in it. The sake is left to stand in a tank for about 10 days to allow the suspended ori particles to settle to the bottom. This process is called oribiki, or ori removal. Following the oribiki, the clear, upper part of the liquid is removed from the tank. Even after the oribiki, fine particles remain mixed in with the liquid, so it is filtered once more. Activated carbon is often used to remove colors and zatsumi off-flavors.

⑥Bottling, Pasteurization, and Storage

The filtered sake is bottled. Active enzymes remain within the sake, so it is pasteurized by heating it to between 60 and 65 degrees Celsius (140-149℉) to deactivate the enzymes and sterilize the product. We call the process "bottle heating," as we dip the sake-filled bottles in hot water. Once they have reached the prescribed temperature, we rapidly cool them, putting the heated bottles of sake in a refrigerator for storage and aging. Depending on the sake, brewing water may be added either before the pasteurization or between pasteurization and shipping to adjust the alcohol content or flavor.


Japanese sake is very sensitive to sunlight (ultraviolet rays) and high temperatures. Even indoor brightness or fluorescent lighting can degrade its quality. Before opening, store in a cool, dark place such as a wine cellar, and keep away from bright lights. After a bottle has been opened, we recommend refrigerating it, as the flavor changes after about two weeks. Those who do not want it to change should drink it as soon as possible. You can also enjoy the changing flavors by opening the sake up and allowing it to breathe like wine, or by storing it at a slightly raised temperature to encourage aging. Those who can afford the risk can try different storage methods to create their preferred flavor.