Sake was first made in Japan over 2,000 years ago, and in the intervening years there have been many different types of sake produced. The first makers of sake would probably not recognize the rice wine of today: evolution and revolution have radically altered the sake brewing process and, indeed, the final product. Nowadays, there are more than 10,000 different varieties of sake produced, and with so many to choose from it can be hard to figure out which sake is right for which occasion. But fortunately there are different classifications to help you choose the sake that is right for you. 

What separates the different types of sake is the production process, where two factors determine the quality of the sake. The first is the "polishing" process, where rice is gently milled to remove the unnecessary fatty acids and impurities in the outer layers of the each grain of rice. Most sake rice is polished to about 80 percent of its original sized kernel. Rice that has been ground to 70 percent or less of its original kernel size is considered high quality. The other factor that influences quality is whether or not distilled alcohol is added during the final stages of production. Alcohol is typically added to increase the yield of each batch, but many of the best types of sake are still made with only water, rice, koji (mold used to convert the rice's starch into sugar), and yeast. 

There are five major classifications of sake, and these can be used to determine the quality level of sake. The first four "high quality" classifications of sake are presented in order, starting with the highest quality: (note – these classifications overlap quite a bit) 

• Daiginjo-shu: Daiginjo sakes use the most highly polished grains of rice in their production: more than 50 percent of the original kernel is milled away to leave only the purest starch elements. With a full flavor and a strong aroma, Daiginjo sakes leave very little aftertaste, making them a good dinner companion. Sakes labeled Junmai-Daiginjo have had no alcohol added during the brewing process.
• Ginjo-shu: Ginjo sake is made with rice that has been polished to at least 60 percent of its starting size. Ginjo generally has a more delicate flavor, and tends to sweeter than other sakes. Ginjo sake can be made with added alcohol or without; if made without adding alcohol, it will be labeled Junmai Ginjo.
• Junmai-shu: Junmai indicates that the sake is pure rice wine with no alcohol added and at least 70 percent polished grain. Junmai sake often has a bold taste that surprises you, and tends to be more acidic than other sakes.
• Honjozo-shu: Honjozo is similar to Junmai in its production, except that small amounts of alcohol are added to take away some of the boldness of Junmai flavoring. Honjozo sakes are lighter and sweeter than others, and taste wonderful when served warm.
• Futsuu-shu: Futsuu is a term that covers the vast bulk of sake produced. Most sake produced and sold has no special designation, and so price is often the best indicator of quality in these sakes. Futsuu sake will have been made with rice that has been less than 70 percent polished, and has alcohol added in much greater quantities than Honjozo sakes.

Another type of sake is Namazake, which is sake that has not been pasteurized. Namazake can be any of the first four classifications of sake, and generally has a livelier and fresher taste. This rare sake should be refrigerated and served cold. 

There are no hard and fast rules about what quality of sake should be served in specific occasions. If you have enjoyed some Futsuu-shu sakes, you may want to experiment with the higher quality sakes to see if you find one that suits your palette. Because of the many crossovers between classifications, though, the best indicator of quality is your own sense of taste – if you find sake that you like, stick with it, and enjoy!