Akazake and mirin, and how they differ: the ash-preserved sake that survived only in Kumamoto

If a bottle of amber liquid labeled "akazake" sits next to the mirin on the shelf, that may be where the food culture of Kumamoto reaches your kitchen.

Akazake is a local sake that barely circulated outside Kumamoto Prefecture. It looks like mirin and is used like mirin, but its chemistry is another matter entirely. The gloss and shine it leaves on a dish, and the soft, full finish, are why cooks around the country ask for it by name.

The difference comes down to acid or alkali

Mirin and sake are both, chemically, acidic. Acid tends to firm up the protein in food, so simmered fish and simmered vegetables come out with a slight tautness.

Akazake, by contrast, is mildly alkaline because of the wood ash, which is unusual. Where acidic mirin tightens, akazake leaves the food soft and full. Its sugars and amino acids also give a deep gloss and shine that some say goes past mirin's.

A little in a rolled dashi omelette and it stays moist and tender even after it cools. That single point is more or less the whole reason restaurant kitchens send to Kumamoto for it.

Why it is alkaline: "akumochizake," ash instead of heat

What creates the difference is how akazake is made. Sake is normally kept sound by pasteurization, a heating step. Before that technique spread, one way to protect sake from spoiling was to add wood ash to the moromi (the fermenting mash). Sake made that way is called "akumochizake" (灰持酒).

The alkali in the ash neutralizes acid and holds unwanted microbes in check. With neither refrigeration nor sterilization available, it was sound reasoning. Over time, akumochizake turns slowly amber as the sugars and amino acids react. That color is where the name akazake, red sake, comes from.

Akumochizake once existed in many places, but disappeared as pasteurization spread. In Kumamoto it did not, partly because the Higo Hosokawa domain protected it, and it is said to have been drunk on as the sake of the province. Otoso at New Year in Kumamoto is still akazake.

A brewery running since the Hosokawa domain: Zuiyo's "Tohi Akazake"

The house keeping this akazake culture going is Zuiyo, a sake brewery founded in 1867 in Kawashiri (川尻), Kumamoto City.

Kawashiri has been a port town since the time of Kato Kiyomasa, and brewing grew up there alongside the shipping. Zuiyo has made akazake here for more than 150 years, next to its sake. "Tohi Akazake (for cooking)" is that sake prepared for the kitchen. You can use it straight in place of mirin, which is how the taste of Kumamoto reaches kitchens elsewhere.

For people in Kumamoto, akazake is otoso, and the taste of zoni soup, and the memory of New Year itself. On the other side of the bottle runs the time of a place, carried down from the days of the domains.

Using akazake: how to swap it in for mirin

• Teriyaki: just swap it for the mirin. The richer gloss shows at a glance
• Simmered fish: the flesh comes out soft and full. Good for mackerel or flounder
• Rolled dashi omelette: a little keeps it moist after it cools, which suits a bento
• Kumamoto-style zoni and otoso: New Year, done the way it is done there
• Sukiyaki dipping broth: cut the sugar and the sweetness still lands, with body

Start by replacing the mirin in your usual teriyaki. The difference in the finish tells you why this sake stayed alive in Kumamoto.

Frequently asked questions

What is the difference between akazake and mirin?

Both give sweetness and gloss to cooking, but their chemistry differs. Thanks to the wood ash, akazake is mildly alkaline, which is unusual. Unlike acidic mirin or sake, it is less inclined to firm up the protein in food, so fish and meat come out soft and full. It also produces a richer gloss and shine, which is why professional cooks order it in.

What kind of sake is akazake?

A local sake of Kumamoto Prefecture, made by an early method called "akumochizake" (灰持酒), in which wood ash is added to the moromi to keep the sake sound instead of heating it. Because it takes on an amber color over time, it is called akazake, meaning red sake, and in Kumamoto it is still drunk as otoso at New Year.

Where can I buy akazake for cooking?

"Tohi Akazake (for cooking)," prepared for the kitchen by Zuiyo, a sake brewery founded in 1867 in Kawashiri, Kumamoto, is available through online retailers including Amazon. It comes in a 1800ml bottle and can be used in teriyaki or simmered fish exactly the way mirin is.