Japanese Oak Lends a Distinctive Twist to This Belgian Whisky (Review)

Mizunara is a wood type that whisky makers love to showcase. This Japanese oak is scarce, difficult to work with, and renowned for its distinctly woody, spicy character. Filliers didn’t settle for a quick finish. The Belgian distillery gave its Master Distiller Mizunara Cask a full two-year finish in Japanese oak casks. But after five years in bourbon barrels, does that influence really shine through?

The foundation for this Belgian single malt was laid in February 2019. For the spirit, Filliers used 100% Belgian malted barley from regenerative agriculture. After distillation, the whisky matured for five years in a first-fill ex-bourbon cask. It then spent another two years in a cask made from Japanese Mizunara oak.

That last part is quite special. Mizunara is not only rare, but its porous structure also makes it challenging to craft into whisky casks. When whisky does spend time in such barrels, the flavors can be remarkable. The wood is often associated with aromas of sandalwood, coconut, and exotic spices.

For this Master Distiller Mizunara Cask, Filliers kept things small. It’s a single cask release with only 393 bottles worldwide. The whisky is bottled at 45.1% ABV and comes without any gimmicks or a mix of different casks.

Once the whisky sits in the glass for a moment, the Japanese oak becomes apparent. First come notes of coconut and vanilla, followed by the first subtle hints of wood. The aroma clearly leans woody and spicy.

Beneath the oak, vanilla remains prominent at first. Give the whisky a little time and both sides sharpen up. On one hand, you have the sweet, familiar notes from the bourbon cask; on the other, the drier, spicier, and woodier character of Mizunara.

It’s a nose that invites you to linger.

With the first sip, the balance shifts notably. While the Mizunara speaks up on the nose, the ex-bourbon cask asserts itself more strongly on the palate. Vanilla and caramel form the base, lending a familiar sweetness.

Soft oak joins in, and as the whisky lingers, some spice emerges. Just don’t expect too much Mizunara—its influence stays subtle in the background, beneath a veil of coconut and spices.

That’s somewhat surprising. A two-year finish is fairly long, and you might expect sandalwood to take center stage. Still, the whisky is well balanced and nicely complex.

Toward the finish, the wood comes back into focus. The sweetness of vanilla and caramel gradually recedes, making way for a drier spiciness.

That’s where the Mizunara makes one last appearance. Not as prominently as on the nose, but enough to keep this from ending like a typical bourbon-matured single malt.

The finish is fairly long, with a lasting interplay of sweetness, spice, and dry oak.

The Filliers Master Distiller Mizunara Cask stands out for the interplay between two very different oaks. On the nose, Mizunara’s woody, spicy character is clearly recognizable. Vanilla and caramel from the bourbon cask support it and provide a lovely sweet backbone.

On the palate, the roles reverse. The ex-bourbon cask takes charge, with vanilla, caramel, and soft oak in the foreground, while Mizunara’s influence recedes further into the background.

That may make the whisky feel less overtly Japanese than you might expect after two years in Mizunara. At the same time, that very finish ensures there’s still plenty to explore—especially on the nose and into the finish.

+ Mizunara is clearly recognizable on the nose.

+ Beautiful combination of spicy oak, vanilla, and caramel

- On the palate, the Mizunara is somewhat overshadowed by the ex-bourbon cask