Mizunara oak. It has a curious ring to it. Scarcer than European and American oak, and much more expensive, its story is deeply rooted in Japanese history.
At the end of World War II, Japan faced shortages of medicine, food and other daily necessities. The lack of imported casks to age whisky was the least of the country’s problems. But the spirit was popular with the occupational armed forces, so whisky makers had to do something. Distillers began to use the native oak, mizunara.
Today, many whiskies from Japan, the U.S. and even Scotland use mizunara. Add the word to any label, and odds are those bottles won’t last long on shelves. Yet, many of these whiskies spend mere months in these casks. So is the allure of mizunara simply a marketing strategy, or does it make for a better spirit?
Behind mizunara’s rarity
Hirotsugu Hayasaka, the previous head cooper of Nikka and one of the industry’s most respected figures, says that there are many difficulties working with mizunara.
The oak does not grow straight, it has a high moisture content and it’s much more porous than other varieties, he says. These issues make the casks prone to leaking. Its name, after all, translates to “water oak.”
Hayasaka says that while Japanese oak from Hokkaido stays together better because of the area’s colder climate, it’s still not great. He believes that American oak is better both in usage and the balance of flavors imparted to the whisky.
Mizunara needs to be around 200 years old before it can be cut and used for casks. While some larger distilleries have access to forests, rights are often suspended to allow them to regrow.
During these times, the available wood is sold at public auctions. The huge demand can cause prices to skyrocket. A single cask now costs more than $6,000.
Distillers both in Japan and abroad have a hard time getting their hands on a cask. It’s a competitive business, and larger producers often get first pick.
The huge demand can cause prices to skyrocket. A single cask now costs more than $6,000.
While maturation time doesn’t define the quality and depth of whisky in general, it’s more important with mizunara. Many distillers and experts claim that whisky must mature in the casks for at least 15 to 20 years for the “right” flavors to be imparted. Any less, and the surfacing notes are too intense and sharp. Harsh woodiness overwhelms subtler flavors.
The mizunara difference
When left to mature correctly, a mizunara-aged whisky offers complex notes of sandalwood, coconut, spice and Japanese incense.
A stellar example is the Yamazaki Mizunara series, with the most recent being the 2017 edition. Aged 18 years in the oak, the whisky’s immense balance delivers a burst of coconut and banana, aromatic incense and summer spice.
Suntory’s Yamazaki distillery is well-known for its management of mizunara, and many of its famed expressions feature the oak’s influence.
The Chichibu distillery, Japan’s most famous and beloved small distillery, goes further with its use. All of the site’s washbacks, the container where wort is fermented, are made from Japanese oak. It’s said to give Chichibu whisky its character.
Pernod Ricard’s 2014 release of Chivas Regal Mizunara, a blend finished in the oak, was originally exclusive to the Japanese market. It took four years before the bottling would be released globally. While the expression is smooth, drinkable and very pleasant, its short time spent in the Japanese casks has imparted almost none of the known mizunara notes.
Similarly, the sought-after Bowmore Mizunara release, which sold out quickly and now sells for double its original $1,000 retail price, spent mere months in the casks.
The Yama whiskey from Bainbridge Organic Distillers on Bainbridge Island, Washington, is aged in 10- and 15–gallon casks, very different to the much larger puncheons (70–100 gallons) used in Japan. The smaller size means that the whiskey comes into greater contact with the wood, so notes are imparted faster.
The exclusive use of Japanese oak in the Bainbridge bottling has created a unique American expression, which brings forth many subtle flavors of coconut, grain and spice.
Distilleries like Bainbridge and Chichibu in Japan are experimenting with smaller casks and different production methods to extract the most from mizunara. Distillers also search for faster, easier ways to use the wood. In the meantime, the best plan is to look to top distilleries known for their well-aged mizunara expressions.
Mizunara: how does it affect whiskey?
So, how do mizunara-finished whiskies taste? We sampled three bottlings finished in Japan’s mizunara oak—a smoky Islay single malt, a mellow blended Scotch and a fruity Irish whiskey—to see how the cask finish transformed these spirits. Spoiler alert: Each is excellent in its own way, like the silkiest version of each base spirit.
For those who prefer brandy to whiskey, later this year Cognac Park will be releasing a mizunara-finished Cognac, the first such bottling of its kind. –Kara Newman
Bowmore Mizunara Cask Finish Single Malt Scotch Whisky
The first single-malt Scotch finished in rare Japanese oak, this limited edition was released in 2015 with only 2,000 bottles produced. Overall, the cask finish serves to mellow this Islay whisky’s smoky core, creating a harmonious mix of sweet spices, vanilla and soft peat, plus the barest hint of mouthwatering salinity. abv: 59.3%
Chivas Regal Mizunara Blended Scotch Whisky
Typical of Chivas, this blended Scotch whisky is designed to be mellow and smooth. The mizunara finish pushes that characteristic even further: The palate sinks into velvety, palate-coating layers of honey, Sherry and almonds, finishing long on clove and ginger sparks. Released in 2014 and intended for the Japanese market, it’s now exceedingly difficult to find but worth the search. abv: 40%
Glendalough Mizunara Finish Single Malt Irish Whiskey 13
This light, fruity Irish whiskey dries out a bit, morphing from typical fresh apple and pear to an intriguing mix of plum skin, unsweetened chocolate and coconut. This particular bottling is aged 13 years in former Bourbon barrels, then finished in mizunara oak. New release for 2018. abv: 46%
Last Updated: May 4, 2023