How different types of cask wood affects your whisky?

Wood has a discernible effect on the taste of your whisky. As discussed in our earlier article, oakwood is the preferred material for making liquor casks, but it too has different variants. Today, we take a look at various types of oakwood and their effect on the whisky maturation process.

About Oakwood

The journey of a cask begins with unadulterated oakwood, wood that is neither painted nor treated with chemicals. Oakwood is readily accessible in the Highlands and offers structural benefits for the construction of casks. It can be altered after harvesting through processes known as toasting and charring to make casks with unique flavoring qualities. Here are some general themes of flavors you can expect from different types of oakwood.

Scottish Oak

Scottish oak is a rare variety of wood and hard to come by due to centuries of deforestation. The tree is rather knotty and gnarly, which makes it difficult to manipulate it for building casks. However, once crafted, the wood provides a warm and spicy character and flavors to the spirits, which we generally associate with single malt Scotch whiskies.

Irish Oak

Similar in properties to the Scottish oak, Irish oak has very little exposure in modern times due to a lack of resources. However, recent experiments suggest that this particular strain of oakwood imparts sweet vanilla, caramel, and chocolate notes to the whiskies. Moreover, the healthy dose of woody, oaky spice in Irish whiskeys can also be attributed to the Irish oak.

European Oak

Oak trees from France and Spain generally qualify as European oaks. Casks made from this wood are used for aging spirits like Cognac and Armagnac and take much longer to impart flavor because of the wood's tighter grain formation. The flavor itself can be wildly different, leaning less towards vanilla and fresh fruit and more towards tannins, citrus, and spice. Moreover, oakwood sourced from Ukraine and Russia also falls under this category but has even denser properties which reduce the wood's impact on flavor.

American Oak

Most American oak casks are first used to age bourbon before being sold for maturing Scotch and other liquors. American oakwood imparts vanillic and fruity flavors to the spirits. However, the new or 'virgin' American oak offers subtly different flavors with hints of spiciness and woody notes melded with vegetal bitterness.

Hungarian Oak

While a part of the European oak family, the Hungarian oakwood is uncommon in whisky maturation. However, in rare use cases, the oakwood imparts a vibrant, oaky spice with soft berry-fruit flavors and traditional European-oak depth.

Mizunara Oak

Mizunara is a slow-growing species of oakwood from Japan. Casks made from Mizunara oak are particularly rare as, like the Scottish oak, the wood is difficult to manipulate. But the distinct flavoring offered by this wood has created a niche demand in the Japanese and international whisky markets. The signature flavors of Mizunara oaks include soft spiciness along with notes of sandalwood, incense, coconuts, and dry tannin.
Other than oakwood, distillers also keep trying spirit maturation with different woods, although with limited success. One of the latest experiments includes Amburana, a tree that grows in Brazilian rainforests. Typically used for aging cachaça, a native sugarcane spirit, Amburana wood has a strong tonka bean character. Think vanilla flavor turned up to eleven and rounded out with aromatic notes of coconut and cinnamon.