Ice, ice ageing

It’s the new category at IWC sake, so clearly ageing sake at low temperatures is not going away any time soon.

 And there’s a new entrant in the category, Ondo (which could be the reading for the Japanese characters for “temperature”) featuring sake aged at -1°C (30°F) for 3 years. 

Ondo are following up their first release, 001 Sparkling Sake 2019, with a second, 002 Vintage Sake 2022, released Friday 28 Feb 2025. Ageing at just below zero for 3 years is intended to combine the freshness and dryness characteristic of Tosa sake with ageing-derived depth, creating a refined flavour profile that can appeal to more than just sake enthusiasts.

Made by the Sento Sake Brewery in Kochi from Aiyama rice polished to 40%, the sake is designed to combine spirited fruity aromas accented with aged notes of nuts, honey and spices with smooth texture and transparency of flavour.

Limited to 120 units, each 720 ml bottle is priced at JPY 16,500, and technical specs disclosed are alcohol 15.8%, SMV +2, acidity 1.8.

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The press release claims that the ageing process involves water molecules enveloping alcohol molecules to create mellow flavours, a delicate reaction that is affected “immeasurably” by temperature. (I only have a BSc, but I suspect that this kind of thing can absolutely be measured. I found some mention of water surrounding/solvating ethanol in ageing, although it was mostly focused on vodka – linked below. Sounds plausible.)

The press release continues on to say that the action of yeast and enzymes is slowed at temperatures between -1 and -5°C (30–23°F), oxidation is suppressed and freshness is retained. This is also confusing, as assuming the sake is pressed normally there shouldn’t be any yeast in it and any enzymes will only be active if the sake has not been pasteurised, which is not mentioned anywhere. Science-washing is a thing.

The concept for Ondo makes more sense in Japanese than English, but with a little verbing of nouns it goes something like “temperature sciences sake“. The label also has a registered “freezing temperature certification mark” with the English text “JAPAN HYO-ON ASSOCIATION” that supposedly shows that freezing-temperature technology provides safe, healthy food with natural flavour. Not sure they thought that one through, from an alcohol and health claims perspective.

There is a Japan Hyo-on Association, which seems to focus on promoting frozen foods. Their site claims that the Japanese terms hyo-on (氷温, chilling/partial freezing temperature), cho-hyo-on (超氷温, ultra/super-chilled temperature) and hyo-on jukusei (氷温熟成, chilling/partial freezing temperature ageing) are registered trademarks, despite hyo-on being a normal word found in any dictionary (and the Kenkyusha dictionary I use also has hyo-on jukusei). Maybe it’s registered in combination with their logo, although that’s not the claim on the site. Japan seems to be fairly lax on what can be registered (“craft sake”, “sake expert” and other wide-ranging and seemingly unregistrable terms are also registered trademarks), and some people are impressed by labels and official marks, that’s all I can think of.

The Sento Sake Brewery site already has a hyo-on chozo junmai daiginjo as well as other innovative production methods such as using deep sea water.

氷温熟成(R)に特化した日本酒ブランド「Ondo」第二弾『002 Vintage Sake 2022』を120本限定 リリース (PR Times, 25 Feb 2025)
Sento Sake Brewery (English)
80 Years of Rapid Maturation Studies — Why Are We Not There Yet? Part 1 of 3 (15 Oct 2017) – Part 2 of 3 (25 Dec 2017) – Part 3 of 3 (16 Sep 2018) (Gary Spedding, Distiller Magazine)
136 Years of Rapid Maturation: Why Are We Not There Yet? (Gary Spedding, Distiller Magazine, 14 May 2024)