Last week, I attended the second class of a course on Japanese wine sponsored by the Japanese Wine Association. The topic was Nagano wine.
The take away?
Nagano’s climate and topography allow the prefecture to produce a diverse range of wine based on grape and style. This along with improved vineyard and winemaking know-how and increased interest in Japanese wine domestically and internationally makes Nagano a wine region to watch out for.
Nagano has low annual rainfall
The greatest critique of Japan as a wine region is that its climate is wet during the wrong time. Rain during the growing season and before harvest is not helpful and down right harmful to producing grapes for quality wine. However, Nagano, which is located inland away from the ocean, has low annual rainfall compared to other parts of Japan. For example, in 2012:
- Nobeoka City in Miyazaki, which also makes wine, had 3174mm of rain;
- Kofu City, which is famous for koshu wine, had 1135mm of rain; and
- Matsutomo City and Ueda City in Nagano had, respectively, 943mm and 868mm of rain.
2012 seems like old data, but climate does not change drastically year to year. The data shows the point that Nagano has low annual rainfall compared to other parts of Japan.
Nagano has high average annual sunlight hours
Grapes need sunlight to ripen. For this, it helps to have more sunlight exposure. Or, in other words, a longer growing season.
Because Nagano has low annual rainfall, its average annual sunlight hours is high compared to other parts of Japan. For example, from 1981 to 2010, the national average was around 1897 hours. For the same period, Nagano’s average was 1940 hours.
Nagano has high diurnality
Diurnality is the difference between day time temperature and night time temperature. High diurnality means that there is a great difference between day and night time temperature. This is ideal for growing quality grapes as it allows grapes to ripen during the day but preserve acidity during the night.
Nagano has high diurnality because, first, it is inland and its temperature is not tempered by the ocean. Second, it is mountainous. If you have ever been camping in the mountains you know how warm it can be during the day–and how chilly it can be once the sun sets.
Nagano has a varied topography
Nagano is long and skinny, running north to south through the upper middle part of Honshu, the main island in Japan. It is mountainous, shaped by volcanic eruptions. In valley areas, it is terraced, shaped by various rivers. This gives it a varied topography. For example, based on the Amerin and Winkler scale:
- Shiojiri City, located in Kikyogahara, a terraced area shaped by the Narai river, has a climate similar to Bordeaux and the southern part of Burgundy;
- Takayama, located in Chikumagawa, an area with varying altitude around the Chikumagwa river, has a climate similar to Champagne and the northern part of Burgundy; and
- Ueda City, also located in Chikumagawa, has a climate similar to northern Italy.
Nagano’s soil is, generally, well-draining
Going back to the first point, while Nagano has less annual rainfall than the rest of Japan, it still has more than, say, Bordeaux. However, Nagano is mountainous and slopes provide good drainage. Also, the several rivers flowing through Nagano mix pebbles and sand into the soil which increases drainage ability.
As proof for the diversity of Nagano wine, here is the line-up from the class tasting.
The grape varieties are (1) Niagra, (2) Sauvignon Blanc, (3) Chardonnay, (4) Syrah and Merlot blend, (5) Merlot and (6) Pinot Noir. Quite a diverse group!
Special thanks to the class instructor Mr. Minoru Numata for the slides from which information in this post is sourced.