Sake breweries vary greatly in size and productionmethods, employing different techniques and technologies at each step. However,the fundamental stages of sake brewing have remained consistent for centuriesand are generally as follows:

Step 1: Rice Polishing
The first stepin sake brewing is polishing the rice, which involves removing the outer layersof the rice kernels, leaving the starchy center. The degree to which rice ispolished affects both the flavor and classification of the final sake. Somebreweries opt to purchase rice that has already been polished.

Step 2: Rice Washing and Soaking
Once polished,the rice is carefully washed to remove the bran, and then soaked in water for aprecise period to ensure it absorbs the right amount of moisture. The soakingprocess requires great precision, with the rice’s weight needing to be accurateto within 0.2% when done by hand.

Step 3: Steaming the Rice
The soakedrice is drained and covered with a cloth overnight. The next day, the rice issteamed in a large vat for 45 to 60 minutes to soften it and make the starchmore accessible for the koji enzymes to break it down. After steaming, the riceis spread out and allowed to cool to the appropriate temperature for the nextstage in the brewing process.

Step 4: Koji Preparation
Rice, beingrich in starch, needs an enzyme to break down the starch into fermentablesugars before it can be turned into alcohol. Unlike beer, where grains aremalted, a mold that digests starch (Aspergillus Oryzae) is cultivated on abouta quarter of the polished sake rice. This is done by sprinkling the mold sporesover steamed, cooled rice, which is then carefully placed in atemperature-controlled room, similar to a sauna, for 3 to 4 days. The moldyrice that results is known as koji.

Step 5: Yeast Starter Mash
The next stepis to combine water, steamed sake rice, koji rice, and yeast to create a yeaststarter mash. The most common modern method of creating this starter mash isthe Sokujo method, which takes about two weeks. However, traditional methodsare more labor-intensive, slower, and less predictable, though they oftenproduce exceptional results.

Step 6: Main Mash (Moromi)
The main mash,or Moromi, is built on the starter mash in three stages over the course of fourdays. The mash is left to ferment for around 20 to 30 days.

Step 7: Pressing the Sake
Afterfermentation, the sake is pressed to separate the liquid from the rice lees.Some sake is allowed to drip naturally from bags, while most is mechanicallypressed using a device.

Step 8: Filtering
Once pressed,the sake typically undergoes further charcoal filtering to refine its flavorand clarity.

Step 9: Pasteurization and Bottling
Most sake ispasteurized and bottled, then stored for about 3 to 6 months. However,unpasteurized sake, is bottled without this process.

Step 10: Final Pasteurization and Shipping
Finally, thesake is re-pasteurized, bottled, and shipped out to markets.