Ever Blurring Autumn Sake: Difference Between Hiyaoroshi & Akiagari

Greetings Sake Lovers,

Perhaps the tastiest sake season is just around the corner. By tastiest we are of course referring to the autumn. The season when the flavour of sake comes full circle.

There are two specific types of autumn sake: hiyaoroshi and akiagari.
But there is still a lot of confusion about the difference between the two.

In this article we attempt to explain the difference between the two and perhaps even clear up the confusion.

What is Hiyaoroshi?

Traditionally, hiyaoroshi begins life as freshly filtered (pressed) sake, completed at the end of the winter just as the trees start to regrow their leaves. This sake is then pasteurized once before being put into storage where it remains over the summer months. This sake is only released when the ambient temperature outside the brewery is the same as storage and the leaves on the trees have started to turn orange (the last bit about the trees is less important). The word hiyaoroshi is made up of the words hiya (cool) and oroshi (shipping). So hiyaoroshi literally means cool shipping.

As sulfites are not used for sake, completed sake is microbially unstable: the koji enzymes, yeast, and other microbes are still alive. In this state it would be difficult to store the sake for long periods without significant changes in flavour and quality. Brewers stabilize the sake by pasteurizing it. Traditionally, this was done twice. Twice was considered the minimum to keep the sake in check. The key is temperature. Super hot temperatures kill microbes, warm temperatures reactivate them and cool temperatures put them in a dormant state. The idea behind hiyaoroshi is that as long as the ambient temperature is the same as the cool storage temperature, none of the microbial processes are reactivated and the sake retains its quality and flavour, even with just one pasteurization.

What is Akiagari?

Early attempts to mature sake over the summer often ended in failure. The results were so bad this sake would rarely see the light of day, certainly not for the consumer. This was called akiochi (literally, fall sake, which makes for an ironic play on words). The word akiochi points to the negative decline in flavour. Eventually, brewers started to have some success with summer ageing. This sake was called akiagari which translates with the opposite nuance, i,e. increase in quality after autumn.

As explained above, due to the unstable nature of sake, up until now the tradition was to pasteurize akiagari sake twice to seal in the quality. And that was the definition of akiagari. We emphasize, was.

Sake Evolution

Sake brewing is constantly evolving. The sake of today is much more stable and higher quality than its descendants. This improvement in quality means that the second pasteurization has become almost redundant. Sake can be shipped with just one pasteurization even when it is still quite warm outside at the end of August. In fact, many breweries now pasteurize all their sake just once as standard.

This evolution means that the difference that existed between akiagari and hiyaoroshi is blurring.

Some breweries have even begun label their autumn sake as simply akishu (autumun sake).

In a way, it’s kind of sad that we have essentially said goodbye to hiyaoroshi and akiagari. But not to worry, there are surely new developments on the horizon to take its place. Hiyaoroshi and akiagari are not completely extinct yet; you will still find many breweries who refuse to give them up just yet.

Autumn Sake Comes Full Circle

Whether the sake is labelled akishu, hiyaoroshi or otherwise, autumn sake is sake that has come full circle. Due to the ageing, the flavour has matured and is generally a lot milder and rounded. Just the sort of flavour profile that matches popular autumnal dishes like mackerel.

For sake pros, autumn is the best season for sake. But don’t take their word for it, try yourself and make your own mind up. But be quick, the season will be over before you know it, and sadly, autumn only comes around once a year.