Nitrogen fertilization of rice plants before flowering affects sake fermentation and quality

Background and Objective Nitrogen fertilizer applied as top‐dressing to rice plants before flowering affects the yield and quality of rice grains. However, little is known about the effects of varying dosages of nitrogen at this stage on the brewing properties of sake using the rice grains. To explore this topic, we cultivated the sake rice cultivar “Koshitanrei” with low and high levels of nitrogen (equivalent to 10 kg and 30 kg N per hectare, respectively) applied 1 week before flowering and then conducted a small‐scale sake brewing test using the harvested rice. Findings Sake made from rice from the low‐N treatment was fermented more efficiently. This yielded a higher volume of sake with a higher alcohol concentration and decreased amino acid concentrations. Conclusions The use of rice from the low‐N treatment enhanced alcohol fermentation, resulting in increased alcohol yield and decreased concentrations of amino acids and related compounds. Significance and Novelty The amount of nitrogen applied to rice plants before flowering affects the fermentation properties of rice grains in sake brewing, and this can alter the quality and sensory properties of sake even though the nitrogen content of rice grains is unaffected.