Hakushu Whisky’s Dedication to Water

The groundwater of the Minami Alps region is nurtured by the granite mountains located just behind the Distillery. This granite, formed deep underground around 14 million years ago, gradually pushed up through the sedimentary rock layers above until it finally emerged at the surface. It is among the newest granites in Japan, whereas large granite formations of the same area, such as the Kii Peninsula, still remain deeply buried underground.

Granite is a type of rock that cooled and solidified slowly deep underground, resulting in large crystals and a tendency to weather easily. The weathered rock allows water to pass through, giving it a strong capacity to nurture groundwater. On the other hand, this also makes it fragile and prone to crumbling.

Sitting atop the massive Hakushu Fault, the mountains are also riddled with a network of smaller associated fault fractures, making the underground water flow extremely complex. This may also explain why the water, despite being from granite, has a relatively high hardness of about 30.

The natural water nurtured by the forest takes about 20 years to reach the aquifer below the Hakushu Distillery. Whisky made using water with a hardness of 30 has a light, fresh flavor reminiscent of young forest leaves and citrus, offering a contrast to the rich and full-bodied whisky produced at the Yamazaki Distillery.

The water used in the whisky mashing process is known as “mother water.” Many whisky enthusiasts say that the ideal way to enjoy single malt whisky is to mix it with its own mother water. We therefore recommend trying Single Malt Whisky Hakushu mixed with Suntory Tennensui Mineral Water (Minami-Alps). You're sure to enjoy a whole new depth of flavor.

Natural Water Sanctuary Minami Alps Initiatives

The geology under our Natural Water Sanctuary Minami Alps is granite. Granite has a great ability to nurture water, but it also has the drawback of weathering easily, making landslides more likely to occur. The photo below shows a slope that has become like a sandy beach after a surface collapse washed away the plants and the forest topsoil.

Ground affected by weathering and surface erosion

In such areas, we use thinned timber to build soil retention structures and cover the ground with jute netting to prevent further soil erosion. We also plant local provenance seedlings.* Ten years later, the forest appears to be coming back, and healthy forest soil is starting to regenerate.

Seedlings grown from seeds collected from native trees in the area, with careful documentation of the collection sites and dates

Example of slope collapse site greening Learn about activities in the Natural Water Sanctuary Minami Alps