Mizunara oak explained 

A man sits on mizanura oak barrels
Ichiro Akuto, the founder of Chichibu Distillery

Picture Sandy Hyslop, a jovial chap in comfortable middle age, bent over to thrust his nose into an empty wooden cask. He has travelled 32km just to sniff out any sour or musty notes – and thankfully found none to worry him.

Instead it smells soft and sweet like a joiner’s workshop, with just a whiff of smoke from the char inside. Hyslop is director of blending and inventory for Chivas Brothers, so you’ll find him sniffing away like this quite regularly.

‘We have to nose every empty cask before any whiskies even go near it to make sure it’s what we’re looking for,’ he says. ‘Touch wood we haven’t had any issues, but we still assess every cask that comes in from Japan.’

So would you if you knew what each one cost.

What is mizunara?

Leaves and branches of a mizunara oak tree

A mizunara oak tree, Quercus crispula

Mizunara is also known as Japanese oak (Quercus crispula) and is native to Hokkaid?, Japan’s northernmost prefecture. It is one of the rarest and most expensive oaks in the world, and is often associated with luxury spirits. Just its name on a label can give prices a boost.

Japanese whisky distillers began making casks out of mizunara soon after World War II. At this time the country faced many shortages, including the imported casks distillers had previously relied upon.

At the same time, demand for whisky was soaring thanks to the western troops stationed there. Distillers had little choice but to start using the local oak, despite its reputation for being hard to work with.

Why is mizunara so difficult to work?

A mizunara tree can grow for 200 years before it is large enough to make into casks. Once felled, each tree will yield less timber than other species of oak; you’d get twice as much from a typical American oak for example.

In addition Japanese oaks grow crooked and their knotty wood has a high water content: mizu-nara translates to ‘water oak’. This means mizunara staves must dry for longer – at least three years. After this time they are less pliable than staves made of other oaks, and so are harder to shape.

mizunara oak barrels

Mizunara oak barrels at Chichibu Distillery

Mizunara wood is also markedly porous, so casks made from it are apt to leak, losing more spirit each year on top of the expected loss to evaporation (the so-called angel’s share). On the plus side, this porous nature means the whisky can soak deeper into the wood and pick up more flavours.

If mizunara demands extra skill and care to turn into casks, Japan’s coopers are evidently up to the task. ‘The casks are an absolute joy to work with,’ explains Hyslop. ‘There’s lots of talk about how difficult it is to get the wood and to make the casks but I don’t see those problems. All I see are the casks that come in that are absolutely fabulous quality. We fill them and get great results.’

Why is mizunara so expensive?

There are strict laws in Japan that limit how much mizunara may be logged each year. Trees grown in Japan’s national forests may not be cut down and must fall naturally – but it is possible to buy trees grown in privately owned forests.

The timber is then sold in blind auctions held between December and March. These are fiercely contested, as supply is tight and demand is high. Mizunara is also highly prized by Japanese carpenters who use its wood to craft luxury furniture. It is in such short supply that only around 200 mizunara casks are made each year. Altogether mizunara casks account for only about one in 10 of the whisky casks maturing in Japan.

This makes mizunara casks dozens of times more expensive than those made of plentiful American oak. They’re even more valuable than a first-fill oloroso Sherry butt made of Spanish oak. ‘It’s many thousands of pounds for each mizunara cask that we bring in,’ says Hyslop (below).

A man at a table with whisky glasses and bottles

Sandy Hyslop, director of blending and inventory for Chivas Brothers

Chivas has a longstanding relationship with a cooperage in Japan. For Hyslop this…

Source : https://www.decanter.com/spirits/mizunara-oak-explained-526736/