The primary ingredient in sake is rice, specifically polished Japonica rice. Sake, a traditional Japanese alcoholic beverage, undergoes a unique brewing process that differs from beer and wine. The rice is polished to remove the outer layers, which can affect taste and quality, thus ensuring a higher starch content. After polishing, the rice is fermented using a combination of mold (Aspergillus oryzae) that converts the starches into sugars and yeast, which then converts the sugars into alcohol. This complex process results in the characteristic flavors and aromas that sake is known for.