What Ryukyu Awamori is made from
Awamori is made from just three ingredients: Thai rice, a black mould called kurokoji or just koji (Aspergillus oryzae), and water.
Until the 1920s, Ryukyu's awamori distillers used locally grown sticky Japonica rice which was also widely eaten across Japan and used for sake production. As the price of this rice rose so they sought a cheaper imported alternative that would maintain the quality of their product. After trials, long-grain Indica rice from Thailand was found to offer several advantages.
Indica rice is firmer and easier to handle than Japonica rice and has a larger surface area for kurokoji mould to coat. It was also found to be easier to control fermentation temperatures and the Indica rice produced more alcohol. Best of all, the Thai rice added an attractive fragrance to the finished awamori.
Today, most awamori distillers use imported Indica rice from Thailand but a few distillers have started using specifically, locally grown long-grain Indica rice.
Black Koji mould
Koji mould (Aspergillus oryzae) is a fungus that provides the enzymes that convert starch in the rice to fermentable sugars. Koji is essential to the production of awamori, sake, shochu, miso bean paste and soy sauce. However, while sake is made with yellow koji, awamori is made using kurokoji (black koji mould).
Kurokoji originated in Okinawa and is used exclusively for making awamori. In a process, known as multiple parallel fermentation, black koji converts the starch in rice to sugars that will in turn be converted into alcohol during fermentation.
Kurokoji produces more citric acid than the white and yellow koji typically used to make sake and shochu. The high acidity helps prevent airborne bacteria from infecting the fermentation mash, important in Okinawa's hot and humid climate. Hence, has the benefit of allowing awamori to be made throughout the year without the need for refrigeration.
Awamori is made using water sourced from Okinawan springs and these springs tend to be hard water but a few distillers have soft water springs.