What temperature should yeast be added during the kō-on tōka-moto process after cooling?

In the kō-on tōka-moto process, which is part of the sake brewing method, it is essential to add the yeast at the right temperature to ensure optimal fermentation. The correct temperature range for adding yeast is 25-30°C. At this temperature, yeast can thrive and become active without getting stressed, which is crucial for a successful fermentation process.

If the temperature is too high, such as in the 30-35°C or 35-40°C ranges, it can lead to increased stress on the yeast cells, potentially inhibiting their function or causing undesirable flavors in the sake. Conversely, a temperature that is too low, like 20-25°C, might slow down yeast activity, leading to a prolonged fermentation period that could affect the overall flavor profile and quality of the sake.

Thus, 25-30°C provides an ideal environment for yeast to start fermenting effectively after the kō-on tōka-moto process has been cooled. This temperature range supports a healthy fermentation, fostering the production of the desired aromas and flavors characteristic of high-quality sake.