To provide a method of producing a matured product derived from grain by using food materials naturally derived from the grain and salt not by fermenting a product using a chemical seasoning or yeast.SOLUTION: A method 10 of producing a matured product derived from rice comprises: a soaking step 20 of soaking washed grain 11a in water 13 for a predetermined period； a draining step 30； a cooking step 40, a steaming step, or a roasting step as appropriately； a cooling step 50 if necessary； a grinding step 60； a kneading step 70； and a maturing step 80. The method adopts means of: soaking the washed grain 11a in the water 13 for the predetermined period； after draining the grain, if necessary, cooking, steaming, or roasting the grain as appropriately, and cooling the grain； grinding the grain； mixing salt 12 and kneading the grain； packing the grain into a container 14； and keeps the container at a room temperature for a predetermined period to mature the product.SELECTED DRAWING: Figure 1【課題】化学調味料や麹菌を使用して発酵させることなく、穀物と塩の自然由来食材を使用して熟成させる穀物由来熟成品の製造方法の提供。【解決手段】洗浄した穀物１１ａを所定時間水１３に浸漬させる浸漬工程２０と、水切り工程３０と、必要に応じて炊き上げ工程４０若しくは蒸し上げ工程若しくは焙煎工程と、必要に応じて粗熱除去工程５０と、磨り潰し工程６０と、練混工程７０と、熟成工程８０とから成り、洗浄した穀物１１ａを所定時間水１３に浸漬させ、水切りした後に必要に応じて炊き上げ若しくは蒸し上げ若しくは煎り上げ且つ粗熱を取り除いた後に、磨り潰して塩１２を混合して練り混ぜ、容器１４詰めして常温下で所定期間寝かせて熟成させる手段を採用する米由来熟成品の製造方法１０。【選択図】図１
