The Wine World’s Best Kept Secret

The Wine World’s Best Kept Secret

Koshu is Japan’s flagship white wine grape, striking a perfect balance of ancient history, unique climate adaptation, and minimalist winemaking artistry. Primarily grown in the volcanic soils of the Yamanashi Prefecture near Mt. Fuji, Koshu produces a wine that “whispers rather than shouts”, embodying a distinct sense of purity, precision, and Japanese elegance.

The Thousand-Year Journey

While modern winemaking in Japan is relatively young, the Koshu grape boasts a history spanning over a millennium. DNA analysis reveals it traveled the historic Silk Road from the Caucasus region through China, eventually adapting to Japan’s unique landscape. For centuries, it was enjoyed primarily as a sweet table grape. It wasn’t until the late 20th century that visionary winemakers recognised its true potential, transforming it into the bone-dry, highly sought-after white wine praised by modern connoisseurs

Braving the Elements: The Pergola & The Pink Skin

Cultivating wine grapes in Japan is an art of patience. The region’s high humidity and heavy autumn rains present constant challenges. Koshu thrives under these conditions thanks to its thick, beautiful, pale-pink skins, which provide natural disease resistance.

To optimise airflow and protect the fruit from moisture, traditional vineyards utilise the “pergola” training system, elevating the canopy high above the ground. In a display of meticulous care, some winemakers even place individual paper hats over each grape bunch to shield them from heavy rains.

Flavour Profile & Evolving Styles

Koshu is celebrated for its delicate, feather-light texture and naturally low alcohol levels, typically between 11% and 12%. Rather than overpowering the senses, it rewards careful attention with subtle layers of bright yuzu, Japanese lime (kabosu), white peach, and a gentle hint of steamed rice.

As global appreciation grows, winemakers are proudly showcasing the grape’s versatility through highly distinct styles:

• The Traditional Fresh Style: This classic style utilises standard, low-temperature fermentation in stainless steel to deliver a light, dry, and incredibly crisp wine. It captures the purest, most ethereal essence of the grape, highlighting vibrant Japanese citrus and a delicate, refreshing finish that is perfect for everyday enjoyment.
• The Sur Lie Classic: Aged on the yeast lees, this technique introduces an enhanced textural depth, crisp acidity, and a distinct, savoury sense of umami.
• The Oak Maturation: A growing number of winemakers are utilising subtle oak maturation; careful barrel fermentation lends a creamy texture, gentle notes of vanilla, and a soft, toasted spice that beautifully complements the grape’s delicate fruit without overpowering it.

The Ultimate Food Companion

Koshu is essentially engineered for gastronomy. Because it avoids overly aggressive oak or overwhelming sweetness, it does not clash with the delicate flavours of traditional cuisine. It is widely considered the ultimate pairing for sushi, sashimi, and lightly battered tempura, cutting through oils while amplifying the natural umami of fresh seafood.

From Local Secret to Global Acclaim

Once a hidden gem of the Yamanashi foothills, Koshu has officially stepped into the international spotlight. A major turning point occurred when it was formally registered by the International Organisation of Vine and Wine (OIV), granting the grape official global legitimacy.

Today, Japan’s flagship varietal is earning the wine world’s highest accolades. Landmark moments have solidified its status, such as family-run Grace Wine capturing consecutive Gold Medals at the world-renowned Decanter World Wine Awards, and boutique offerings like Suntory’s Tomi Koshu making history by claiming the ultimate “Best in Show” title. No longer just a regional curiosity, Koshu is celebrated by sommeliers from London to New York and even Hong Kong as a masterclass in elegance, transparency, and liquid Zen.

Written By: Kyle Oosterberg 
Winemaker, Educator and Wine Ambassador for Wine ‘N Things