Ricewine is not wine. Technically it’s beer. What is the difference betwenn Wine and Beer? Well Wine is made by fermenting the natural sugar’s of fruits like glucose and fructose. Rice and other grains contain starch which is unfermentable by yeast and needs to be broken up into smaller pieces – sugars – that can be fermented by yeast. In Beerbrewing, a biotech process, this is done by heating malt to the point of the highest enzyme activity which is around 50-60°C. Malt contains amylases which convert starch into fermentable sugars like maltose.
Rice will be polished and steamed and then mixed with Aspergillus Oryce, a mold. This so called Koji will ferment a week and then yeast and water are added. Aspergillus oryce cracks the stach with enzymes like amylases, glucoamylases and proteases and provides the nutrients for the following yeast fermentation. The next days steamed rice, fermented rice and water are added. The finished ricewine has around 18-20%Vol. and is often diluted to 15%Vol. The amout of polished rice differs in the different types of sake also. Like other „beers“ maturation and aging is required to smooth out the taste.