In sake production, what does steaming help to achieve specifically?

Steaming in sake production primarily serves to gelatinize the starches present in the rice. This process is crucial because it transforms the raw starches into a form that can be enzymatically broken down by the koji mold (Aspergillus oryzae) during fermentation. When the rice is steamed, the heat causes the granules of starch to swell and absorb water, leading to their gelatinization. Once gelatinized, these starches become more accessible for enzymes, which convert them into sugars that yeasts can then ferment into alcohol. This step is fundamental in the sake-making process, as it directly impacts the efficiency of sugar conversion and, consequently, the overall quality and yield of the final product.

While steaming may also indirectly support fermentation processes or improve the texture of the rice, its primary role is aligned with the gelatinization of starches, which is essential for effective fermentation and alcohol production later in the brewing process.