Japan is located between 30 to 50 degrees north latitude, the same latitude as world famous wine regions France, Germany, Italy, Spain and California. That said, Japan’s climate is almost not suitable for growing wine grapes because (1) the weather influenced by nearby Asian continent can be volatile, (2) the intense seasonal change, and (3) the high amount of rainfall/precipitation.
But despite that, there’s one place in Japan that wine grapes can thrive and that is Koshu region in Yamanashi prefecture. Koshu region is surrounded by 4 tall mountains ranging over 6,560 ft, Mt. Fuji in the south, Akaishi Mountains (also known as Southern Alps) in the west, Yatsugatake Mountain in the North and Okuchichibu Mountains in the east. These mountains minimize the weather influence from nearby Asian continent, producing areas with pleasant sunny weather and low rainfall/precipitation.
Compared to famous wine regions in Europe, Japan’s soil is too fertile to grow wine grapes. However, Koshu region’s high altitude (3,600 ft – 4,200 ft), low rainfall/precipitation, extended sunny days and excellent drainage produce a soil with low absorption of nutrients.
There are two factors affecting the drainage, (1) the high elevation and inclined slope means water flows rapidly, and (2) volcanic rocks contained in the soil. Basalt and andesite are a type of volcanic rocks formed after the eruption of nearby mountains and are extremely hard and heavy, with low water retention.
Basalt and andesite are alkaline rocks, which inhibits the fermentation of mulch that helps fertilize the soil. This directs the wine grapes to extend its roots but deeper to absorb nutrients from the different layers of soil. This affects the composition of the wine grapes and determines the flavor of the wine.
Japan’s high volume of rainfall and high humidity causes mold to grow easily and kills the grape trees. To prevent this, growers use horizontal trellis method, which has been used since the Edo period. And as a countermeasure to prevent hail and birds from getting to the grapes, growers carefully enclose each grapes in white paper or plastic bags. This labor intensive process forces the price of grapes to go up, however, in the last decade, Koshu wine has greatly improved its quality through research and improvement of brewing technology and equipment. Katsunuma Jyozo Winery and Mercian are currently the top wineries in Japan making wines using world class brewing technology in a premier facility.
Koshu grapes are much larger compared to the wine grape varieties used in Europe. It has thinner skin with less grape extract that yields delicate and elegant flavor. The genetic analysis conducted by UC Davis in 2004 confirmed that Koshu grapes variety is the same as Vitis Vinifera, which explains why Koshu grapes tastes very similar to Albariño, Pinot Grigio, Pinot Blanc and sometimes Sauvignon Blanc.
While it’s always a challenge to introduce new products to the market, Koshu wines might be something Millennials would be interested in. Gen Y or Millennials (born 1977 to 1995) are the largest workforce in the US and are the leading customers in the marketplace. Millenials likes new things, gets the information by themselves, and incorporates the opinions of friends. They are not swayed by old-fashioned customs and are willing to pay more money for good things. Koshu wine is a very well-balanced wine that pairs exceptionally well with delicate flavors of Japanese food and California cuisine.