Koshu: a Japanese grape variety sometimes used for winemaking
I had not tried many wines made with the koshu variety until earlier this week, when a tasting organised in Paris by the association called Koshu of Japan gave me the opportunity to try about a dozen of them in an hour or so.
These pictures show the colour of the Koshu grape, its long bunches, and the little paper hats used to protect these from storms as harvest approaches. The trellising is the pergola system.
Koshu is an unusual variety in that its skin is a pinkish-gray colour, but its juice is very pale, almost white. It has apparently been known in Japan since the 12th century (some say earlier), where it may have been introduced by Buddhist monks coming from China. For most of the time since then it has been used as a table grape, but quite recently it has been vinified, at first as a sweet or semi-sweet wine, but now increasingly as a dry and rather lively (ie acid) wine with a relatively low alcohol level (between 10,5% and 12% in the case of the samples I tried). Some sources say that it travelled to Japan via China from the Caucasus region, following Marco Polo. Others say it is in fact a hybrid between vitis vinifera and some indigenous grape species. If anyone can enlighten me further, I would be grateful.
There are not a lot of wine grapes planted in Japan, although it is a considerable and sophisticated wine market. This is due essentially to fairly unsuitable climate conditions, with rainfall at the wrong time of year and risks from typhoons and so on. There are, I understand, about 500 hectares of koshu grapes planted and about 90% of these are in the region of Yamanashi, which lies around the lower slopes of Mount Fiji, about 100 kilometres west of Tokyo. Whilst the use of Koshu as a table grape has declined over recent years, experiments in altering traditional cultivation techniques to adapt it better to wine making have gone forward. The old way can be seen in the photograph below, using the pergola system where the vine ends up as thick as a tree and with very long stems. This is not the best way to control yields from the vine, so various vertical shoot systems, such as the Scott Henry trellising method, have been introduced. Several consultants, from Australiea New Zealand and even France have been helping the producers with some ideas recently.
Koshu is a robust grape with thick skins, which helps it resist during the wet periods that can hit the vineyard. The dry wines I tasted were very pale in clour, mostly bone dry, with low alcohol and high acidity. The vast majority of them had been fermented in tanks and bottled young, from the latest 2011 vintage. The occasional one had received some barrel ageing and was thus rounder and softer. On the whole I preferred the tanks ones, but I would not say that these wines would be to everyone’s taste. An idea? Well, a kind of mix between a Trebbiano and a dry Riesling would be near the mark. In other words quite acidic, with delicate aromas, not a huge amount of character, but a lightness of touch that I found attractive.
The wines I liked best from this tasting were the following :
Alps Wine, Japanese style Koshu 2011
Seems a bit weightier than the announced 11,5% alcohol and I also felt there was a bit more residual sugar than the announced 1,1 grams. Still was fine and vibrant. Good and relatively intense for the series.
Grace Wine, Koshu Kayagatake 2011
Delicat and floral, very lively. Pure and dynamic
Yamanashi Wine, Sol Locet Koshu 2011
Fine, delicate and precise.
Yamanashi Wine, Sol Locet Koshu 2010
One of the few “older” wines available at this tasting, I thought it showed more complexity and length than the others.
Suntory Tomi No Oka Winery, Tomi No Oka Koshu 2010
This has been aged in oak and so was rounder and seemed riper than the others. It has much lower acidity than most and would probably be easier for international markets to appreciate. Very silky texture.