Funaguchi - Japan's first Nama-Sake that launched in 1972 - is an un-pasteurized and un-diluted type of Sake and as such it is surprisingly delicate. The most damaging elements to the quality of sake (particularly un-pasteurized) are light, heat and air. So in order to deliver the unique taste of freshly brewed Sake, KIKUSUI had to revise its brewing techniques. In order to protect this delicate Sake from the damaging light rays, they decided to use aluminum cans to completely block out the light. Then they filled the normally 180ml cans right to the top, to 200ml, to reduce the amount of air that could come into contact with the Sake. This way they could allow more people to enjoy the flavor of pure Sake previously only available to those lucky enough to visit the brewery.