Koshu: A distinctly Japanese elixir with a growing stable of styles

By Jo Gilbert

Published: 07 February, 2022

It’s difficult to gauge how much is known in the UK about the white wine grape Koshu. Hailing almost exclusively from Yamanashi prefecture’s Katsunuma region – the ‘birthplace’ of Japanese viticulture – the wine remains largely shrouded in mystery to the UK trade, despite Koshu of Japan’s faithful annual tastings.

Things became a little less veiled last month however, thanks to this year’s digital and memorable takeover by presenters Joe Wadsack and Jane Parkinson. Via the tasting of eight wines, which included barrel fermented, natural, orange and aged – and all with a relatively low 11-12.5% abv – the pair showed that Koshu is becoming a grape for all seasons. All drinking seasons, at least.

Grown in Yamanashi since 718AD, Koshu is Japan’s very own Vitis Vinifera grape… sort of. Having likely migrated from an area spanning the Caucasus to Macedonia, Koshu appears to have picked up DNA potentially from east Asian Labrusca variety along the way. This cross-pollination turned out to be quite handy in fact, giving Koshu the genetic chops to fight off rot in Japan’s “fearfully humid” summer months.

Diversification has exploded since Koshu was officially recognised by the OIV in 2013, with sparkling, oaked, orange and aged wines all now coming to market.

As Wadsack said, Koshu producers have realised that “in order to create value for the export market, they will have to reinvent in some ways”. He continued: “Adding orange or sparkling wines adds huge amounts of value to what is already quite an expensive product. There’s been a massive bifurcation and diversification of different styles over the past five years, which is quite exciting.”

Despite efforts to diversify for western markets, there remains a unique strain of umami-esque salinity and delicacy that keeps the wine a very Japanese proposition. You can taste the cool mountain influence of the Kofu basin – the beating heart of Koshu – which also acts as the sun trap that is needed to get the most out of the grape.

“You have these real extremities of heat and coolness, which can be useful in terms of developing these flavours,” Parkinson said.

Winemaking in the basin is an intensely delicate exercise. Humidity and disease pressure are high, leading winemakers to employ labour-intensive techniques to mitigate the effects. These include fitting individual bunches with tiny plastic ‘umbrella hats’ to stop precipitation lingering on the high pergola vines.

This delicacy carries over to the wines themselves, which can act as a food-friendly blank slate in the vein of Melon de Bourgogne, with delicate citrus notes, minerality aplenty and light lees ageing adding texture to what can be an otherwise thin stew.

Grace Wine offers perhaps the most typical look at what the region has to offer. It is probably the best-known name and in widest distribution in the UK. Its Koshu Hishiyama Vineyard Private Reserve 2020, for example, displays Koshu’s hallmarks: delicate citrus flavours, complex structure and teasing, mineral salinity.

Other styles are in full flow, too, with the 12-month barrel aged Aruga Branca Pipa, from Katsunuma Jyozo winery, compared to a softer Petit Chablis.

There is also the natural, minimal intervention wine, Kurambon, which is unfiltered and made from indigenous yeasts, and Lumiere’s Prestige Class Orange, which is brought to the UK by Amathus Drinks.

Overall, the tasting not only showcased the diversity of Koshu styles, but an immense amount of craft and skill. Kurambon’s N (for ‘natural’) Koshu, for example, is even more impressive given the clinging humidity the region, which is one of the warmest in Japan. But that’s in keeping with Japan’s modern winemaking scene. It’s full of pleasant surprises.

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