Imo Shochu (Sweet Potato Shochu)

Prepare the rice koji: Thoroughly wash and soak the Japanese short-grain rice for 6-8 hours. Steam the soaked Japanese short-grain rice until translucent but still firm. Spread the steamed Japanese short-grain rice on a clean surface and cool to approximately 30-35°C. Evenly sprinkle the Koji mold spores over the cooled Japanese short-grain rice and mix well. Incubate the inoculated Japanese short-grain rice in a warm, humid environment (around 30°C) for 40-48 hours, turning periodically, until the rice grains are covered in a white, cotton-like mycelium. This is your rice koji.

Prepare the primary mash (Ichiji Moromi): In a sterilized fermentation vessel, combine 2000 grams of Filtered water, 200 grams of the prepared rice koji, and the Sake yeast. Mix thoroughly. Cover the vessel loosely and allow it to ferment at approximately 25-28°C for 5-7 days, stirring daily. This creates the yeast starter.

Prepare the sweet potatoes: Wash, peel, and cut the Sweet potatoes into uniform pieces. Steam the Sweet potatoes until they are very soft and easily mashed. Allow the steamed Sweet potatoes to cool to approximately 30°C.