Sake is one of the most popular drinks in Japan, and plays an integral role in Japanese culture and tradition. Sake has been made in Japan for over 2,000 years, and significant advances have been made in the production process throughout the years. Though it is called rice "wine," the process of making Sake has more in common with the brewing of beer. The parallels with beer are many, because unlike wine sake is not aged for more than six months. But sake should not be compared too closely with beer, because it is not carbonated, and is also considered a healthy drink because many of the impurities in the rice are eliminated during the lengthy and complicated brewing process. 

Sake has basically four ingredients. The first and perhaps most important is rice, and there are approximately 46 types of rice used to produce sake. That may not seem remarkable until you consider that there are more than 120,000 different varieties of rice in the world. Sake rice is selected because it is has a larger kernel, and also because it is easier to work with than other grains. In the first step of the brewing process, the rice is "polished:" machines mill the grain of rice to eliminate the outer layers, leaving only the starch-rich "packet" in the center of each grain of rice. Interestingly the milling process was once completed by hand, or rather by mouth. Ancient sake production saw "chewing parties" as part of a Shinto fertility rite: a whole village would chew the grains of rice with nuts and spit the chewed product into a large tub. Fortunately for quality control standards and hygiene, this practice of producing kuchikami no saké ("chewing in the mouth saké") has long since been discontinued. 

The polished rice is then steamed, and "koji" is scattered folded into the steamed rice. Koji is a yellow mold (also known as Aspergillum oryaze) that is grown very carefully by the brewmaster (toji) in a dark place. The koji grows on the steamed rice, and converts the starch in the rice into sugar. Yeast and water are then added to the mixture, and the quality of both of these ingredients plays a major role in determining both taste and quality. The yeast most commonly used is known as Saccaromyces cerevisiae, but the experienced toji often experiment with other types of yeast. The type of water used ranges from mountain spring water to desalinated water from the ocean – the important factor in both is mineral content, and of course water that has not had chemicals like fluoride added is essential. The mixture of yeast, rice, koji, and water (known as "mash") is then allowed to ferment for between 18 to 35 days. The temperature the mash is kept at helps to determine the strength and dryness of the sake produced. 

Once the mixture has fermented, it is "pressed" to separate the liquid from the mash. Traditional preparation methods included placing the mash in canvas bags and then squeezing the liquid out of the bags using a wooden box known as a "fune." Modern methods use a machine that looks a little like a giant accordion. The extracted liquid is then filtered, and is often pasteurized to kill off unwanted bacteria. Most sake is then aged for up to six months to increase its potency and flavor, and then more water is added to increase the yield and lessen the alcoholic content. 

The resulting product is then sold to the consumer, and can be served alone or in cocktails. Most sake is best consumed fresh, rather than leaving it to age any further. There are more than 10,000 different varieties of sake, and though there may be slight changes in the brewing process, the steps outlined here form the basis of all sake production.