This sake is not “pressed” in the conventional sense.

Rather than placing the moromi fermentation mash into sake bags and applying pressure, Katsuyama separates the liquid using centrifugal force.

DIAMOND AKATSUKI takes this approach even further with what the brewery calls “Ultra-Core Centrifugal Extraction” — a completely contact-free, pressure-free process in which the sake is separated without touching either sake bags or sake lees.

The idea is not to add more complexity after brewing.

It is to ask a simpler question:

How purely can the sake created from rice be extracted?

That pursuit is why Katsuyama describes DIAMOND AKATSUKI as a “liquid diamond.”

Translating the “4Cs” of a Diamond into Sake

The name DIAMOND AKATSUKI draws directly from the standards used to evaluate diamonds.

Katsuyama interprets the four “Cs” through sake:

Cut — precision and definition
Color — transparent brilliance
Clarity — purity without distraction
Carat — density and presence

The goal is not simply to create a light, transparent sake.

DIAMOND AKATSUKI is designed to combine clarity with substance — a sake with a defined structure and depth, yet without unnecessary heaviness.

Transparency and presence, held at the same time.

That is the idea behind the bottle.

Beyond Conventional Centrifugal Separation

In most sake production, the liquid is separated from the moromi by pressing it through bags or a mechanical press.

Katsuyama instead has developed sake using centrifugal separation, allowing the liquid to be extracted without conventional pressing.

Its sake “Akatsuki” already uses centrifugal separation, but DIAMOND AKATSUKI goes one step further with the brewery’s Ultra-Core extraction method.

The principle is simple:

No contact with sake bags.
No contact with sake lees.
No pressure.

Rather than correcting or refining the sake after extraction, the intention is to reduce unwanted influence from the very moment the liquid is separated from the mash.

That extraction method — not merely the polishing ratio — is central to the identity of DIAMOND AKATSUKI.

Yamada Nishiki Polished to 35% — and What Happens After

DIAMOND AKATSUKI is made entirely from Yamada Nishiki grown in Hyogo Prefecture’s Special A district.

The rice is polished to 35% of its original weight.

Today, there are premium sake with even lower polishing ratios, so the number itself is only part of the story.

What makes DIAMOND AKATSUKI particularly interesting is what happens after the rice has been polished and brewed.

Once extracted, the sake is stored at approximately −5°C under ice-temperature conditions.

Katsuyama uses this low-temperature storage to help preserve the definition and freshness of the sake while limiting oxidation.

In other words:

Polishing to 35% is not the end point.

The rice polishing, fermentation, extraction and storage are all treated as one continuous process, designed around what should remain in the final sake — and what should not.

Created in 2010 as Katsuyama’s Highest-Specification Sake

DIAMOND AKATSUKI was first released in 2010.

At the time, Katsuyama positioned it as the brewery’s highest-specification sake, bringing together the philosophy, theory and technical experience of brewer Mitsuaki Goto.

The history behind it stretches much further back.

Katsuyama traces its origins to 1688, when the Izawa family began brewing sake in Sendai. In 1857, the brewery was appointed an official sake supplier to the Date family, lords of the Sendai domain.

More than three centuries later, however, DIAMOND AKATSUKI does not rely on tradition alone.

It uses modern centrifugal technology to explore how precisely sake can be produced.

A brewery with more than 330 years of history chose innovation, rather than simply preserving an old method.

That contrast is one of the most interesting aspects of this bottle.

Begin at 7–12°C

Katsuyama recommends serving DIAMOND AKATSUKI initially at around 7–12°C.

Starting chilled and allowing the temperature to rise gradually makes it possible to follow how the aroma, texture and depth develop in the glass.

The brewery also recommends enjoying its sake from a wine glass, particularly when served chilled.

For a sake such as DIAMOND AKATSUKI — where aroma, texture, precision and finish are all important — that approach is particularly appropriate.

This is not simply a sake defined by a high rice-polishing ratio.

The more interesting question is what changes when the extraction process itself is reconsidered.

DIAMOND AKATSUKI was created as one answer.

Katsuyama DIAMOND AKATSUKI 720ml

Miyagi, Japan | Katsuyama Sake Brewery | Junmai Daiginjo | 100% Yamada Nishiki from Hyogo Special A District | 35% Rice Polishing Ratio | Ultra-Core Centrifugal Extraction | 720ml | 16% ABV

Extracted without pressure or contact with sake bags or sake lees using Katsuyama’s Ultra-Core centrifugal method, then stored at approximately −5°C. The brewery describes DIAMOND AKATSUKI as its “liquid diamond.”

Available at IMAMI

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