IWA 5 Junmai Daiginjo Sake Assemblage 4 720ML is a blended junmai daiginjo sake from Toyama, Japan, bottled at 15% ABV. This fourth assemblage marks a milestone it is the first blend created entirely on-site at Shiraiwa Kura by Richard Geoffroy, former chef de cave of Dom Prignon, who joined the project after his 28-year tenure at the iconic Champagne house. The sake is poured in over 130 Michelin-starred restaurants worldwide, 40 of which hold three Michelin stars.
Quick Facts: ABV: 15% | Origin: Toyama Prefecture, Japan | Junmai Daiginjo, Assemblage 4 | Brewery: Shiraiwa Kura
Production & Heritage
Shiraiwa Kura sits at the foothills of Tateyama in Toyama Prefecture, a region prized for its pristine snowmelt water and centuries-long sake tradition. IWA 5 is built around the concept of assemblage a term borrowed from winemaking blending genshu (undiluted sake) made from three rice varieties: Yamada Nishiki (sourced from Hyogo and Toyama), Omachi (from Okayama), and Gohyakumangoku (from Toyama). Each component is fermented with one of five different yeast strains, including experimental varieties, and the rice is polished to a refined 35% ratio. The brewing relies predominantly on the traditional Kimoto method, a labor-intensive process that builds a natural lactic acid starter for deeper complexity. After blending, the sake is pasteurized in-bottle. While the first three assemblages were composed remotely by Geoffroy during pandemic restrictions, Assemblage 4 represents his first full hands-on creation from within the brewery walls a distinction that collectors and sommeliers have noted as a turning point for the project.
Tasting Notes
Aroma: The nose opens with delicate melon and pear, followed by white flowers and a subtle violet fragrance. Underneath those fruit tones, faint marzipan and a wisp of woodsmoke add quiet depth.
Taste: The entry is light, focused, and supple, coating the palate with a silky viscosity. Ripe stone fruits particularly peach emerge at mid-palate alongside hazelnut and candied almond. As the sake develops, mushroom-like umami surfaces with hints of dashi, bonito broth, and soy, building richness without heaviness. There is a subtle minerality that ties the fruit and savory elements together.
Finish: Clean and elegant, with lingering honeyed sweetness and a trace of white pepper. The finish is medium-long, leaving a rounded impression and gentle shiso-like herbaceousness that invites the next sip.
How to Drink IWA 5
IWA 5 is designed to reward multiple serving temperatures. At chilled (10C15C), the fruit and floral notes dominate; warmed to 35C45C, white pepper, shiso, and candied almonds gain prominence, and the umami deepens considerably. Experiment freely Geoffroy himself encourages temperature exploration as central to the IWA 5 experience. In cocktails, the sake’s structure and layered complexity make it a compelling base: try it in a Sake Martini, where its viscosity and minerality replace vodka’s neutrality with genuine character; in a French 75 riff substituting sake for gin, its floral aromatics harmonize naturally with lemon and sparkling wine; or in a Highball with premium soda water and a shiso leaf garnish, allowing the delicate fruit and umami notes to stretch into a long, refreshing pour.
Best For
Gifting a wine or Champagne collector who is exploring premium sake for the first time
Pairing courses at an intimate omakase-style dinner at home
Celebrating a milestone occasion with something rare and conversation-worthy
Introducing a fine-dining enthusiast to the assemblage concept in sake
Frequently Asked Questions
What does IWA 5 taste like? IWA 5 Assemblage 4 opens with melon, pear, and peach fruit, then transitions into a rich, umami-driven mid-palate with mushroom, dashi, and hazelnut complexity. The texture is silky and rounded, finishing clean with honeyed sweetness and a touch of white pepper.
How does IWA 5 compare to Dom Prignon? The comparison is natural given that Richard Geoffroy created both, but the products are fundamentally different Dom Prignon is a vintage Champagne built on carbonation and acidity, while IWA 5 is a still sake built on umami and texture. What they share is an assemblage philosophy: blending distinct components to achieve a seamless whole greater than its parts.
Is IWA 5 good for sipping neat? IWA 5 is specifically designed for neat enjoyment across a wide temperature range, from chilled to gently warmed, and its layered complexity reveals different characteristics at each temperature point.
Where is IWA 5 made? IWA 5 is brewed at Shiraiwa Kura, located at the foothills of Mount Tateyama in Toyama Prefecture on Japan’s western coast. Toyama is renowned for its pure snowmelt water and longstanding sake-brewing heritage.
What foods pair well with IWA 5? Sashimi and raw oysters highlight the sake’s minerality and umami; grilled lobster with butter mirrors its silky richness; aged hard cheeses like Comt bring out the hazelnut and marzipan notes; mushroom risotto echoes the earthy, savory mid-palate; and light tempura with salt rather than dipping sauce lets the delicate fruit and floral aromas shine through.
What sizes does IWA 5 come in? The standard bottle size for IWA 5 is 720ml, which is the traditional format for premium Japanese sake.
Is IWA 5 worth the price? IWA 5 positions firmly in the ultra-premium sake tier, competing not with everyday junmai daiginjo but with luxury collectibles and fine Champagne. Its limited-assemblage releases, pedigreed creator, and placement in the world’s top Michelin-starred restaurants reflect a product aimed at serious collectors and fine-dining enthusiasts rather than casual drinkers.
Why IWA 5?
Assemblage 4 is a pivotal release in the IWA 5 story: it is the first time Richard Geoffroy blended the sake entirely on-site at Shiraiwa Kura, bringing the full force of his sensory training and assemblage expertise to bear in real time rather than through remote tasting samples. The blend itself is genuinely complex three rice varieties from four origins, five yeast strains, and a Kimoto-driven fermentation, all polished to 35% and unified into a seamless whole. Its presence on the wine lists of over 130 Michelin-starred restaurants is not marketing theater; sommeliers at those establishments have chosen it because it holds its own alongside top Burgundy, Champagne, and fine wine. For anyone seeking a sake that bridges the precision of Japanese brewing with the blending philosophy of elite French winemaking, Assemblage 4 is the most complete expression of that vision to date.