Marvelous aging of sake in the magnificent silver mine.

The great wonder of nature, Ikuno Silver Mine
Located in the northernmost part of Banshu, Ikuno Silver Mine was opened in 807. The full-scale mining started in 1542 and reached its peak in the Edo Period when the mine was treasured by the Tokugawa Shogunate. This is a 350 km-long-100 km-deep mine where approximately seventy kinds of precious metals ranging from gold to silver to copper to zinc had been mined before it was closed in 1973. Since then this mine has been in eternal silence.
Maturing into good quality sake with a mellow and soft taste.
It is a pity that many people believe they had better drink sake without aging. Newly made sake has a sour taste of carbonic acid and a pungent aroma of ester, but storing it for a certain period of time matures it into sake with a mellow and soft taste, as its sourness and pungency weaken. Like aged wine, good quality sake like "Daiginjyoshu" and "Ginjyushu" will have a subtle blend of several flavors(sweetness, sourness, pungency, and astringency) and a mellow fragrance. Unlike wine that takes years to age, however, sake matures in only one to three years. Ikuno Silver Mine is an ideal place for the aging of sake at a temperature of around 10 and a humidity of 90% throughout the year. This allows sake kept inside the bottle to have little contact with the outside air. Daiginjyoshu Gaku is the product of marvelous aging in the natural storage place for sake, Ikuno Ginzan.