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Jan 14, 2023

HOW TOKoshu: The Rarefied World of Aged Sake

The vast majority of sake is best when fresh, but there is a niche market for aged sake – known as koshu – that has been aged for at least three years, or much longer.

Jan 14, 2023

Shinsu vs koshu: Differentiating sake varieties

Sake, more commonly called nihonshu in Japan, is a rather complicated drink, like any great alcohol. Beyond “dry” and “sweet,” sake specific terms like nigori and junmai can even leave locals confused regarding the details of this intricate yet delicious beverage.  Japan’s most famous spirit comes in many forms, such as  junmai ginjo and honjozu, though type alone isn’t the only way to distinguish between them.

When a particular batch of sake was brewed also makes a difference – Shinsu sake and koshu sake mean “this year’s sake” and “last year’s sake” going by the dictionary, but the formally titled jukusei koshu – now just koshu – has grown into its own rarified world of aged sake. These often ferment for at least three years before unbottling.

An age-old idea: Making history

The idea of aged sake may turn a few heads at first, as it’s not exceedingly common even in Japan. Unlike wine and whiskey, where it’s no big secret that many bottles only get more tasty with age, the vast majority of sake gets consumed within a year after brewing. Despite this, records show that even as far back as the 1200s, nobles would age sake for about three to five years to similarly enjoy its more complex taste.

The idea of aging sake never caught on much with the lower classes, and by the 1700s alcohol taxes were so high no brewery would want to wait years to see a profit on their labor. These days however, there is a small but growing interest for aged koshu sake, but those curious should know it’s almost a different beverage.

Taste-testing historical flavors brought back to life

In its most intense iterations, koshu aged sake can take on a deep brown color, with a corresponding intensity and richness. Most varieties of commonly enjoyed shinshu (new) sake, normally drunk within a year, offer a fresh and subtly sweet taste. A true jukusei koshu, depending on its age, may flourish with notes of cinnamon, dried fruits or nuts. However, not all aged sake takes on this intense profile. Like any alcohol, the type of sake and the aging method directly influences the final product’s flavor.

Some may take on the color of black miso, where others may appear and taste like the sake we know, yet with a more pronounced flavor. One won’t know how nihonshu tastes looking at the label alone, and that mystery only deepens when dealing with aged sake.  Perhaps your curiosity is piqued, but you don’t want to spring for a legendary 10 year old bottle just yet. Where do you start?

Enjoying koshu doesn’t need to be overly fancy

Unlike expensive bottles of wine that require decanters and specially shaped glasses to get the most refined flavor from your drink, koshu sake requires nothing more than a sake cup. A regular wine glass will certainly do in a pinch. You’ll want to drink your aged sake at room temperature to best take in its complex aroma, in addition to enjoying the more sophisticated flavor.

The biggest issue you may run into if curious about koshu sakeis simply finding some. You may be unlikely to find a bottle in many Western liquor stores. Even if you don’t have a specialty shop in your area, Japanese sake distributors have almost certainly set up an online shop in your country!