Awamori is the oldest distilled alcoholic drink in Japan, and is believed to be the predecessor of shochu. Indica, also called Thai rice, is malted, becoming koji, which is then fermented with the addition of water and yeast before undergoing a single distillation to complete awamori. This technique is said to have remained almost unchanged for 500 years.
One of the distinct features of awamori involves the black koji mold. The mold generates a large amount of the strongly bactericidal citric acid, and is optimal for making sake in Okinawa, a hot and humid place where bacteria easily grow. The koji mold is unique to Okinawa and is used in no sake brewing technique outside of awamori. Thai rice is used instead of Japanese rice is because Thai rice, being hard and smooth, can facilitate the extension of the hyphae of the black koji mold. In other words, it makes the production of malted rice easier.
More than anything, awamori is characterized by its long-term storage, which allows its ingredients to mature and add a mellow savor to it. If stored for three years or longer, awamori can be referred to as kusu, or aged sake.