The types of wood used in the whisky inudustry

The art of whisky production leverages a rich variety of wood types and cask histories to craft spirits with unique and complex flavor profiles. While oak remains a staple in the industry, distillers around the world are increasingly experimenting with alternative woods such as chestnut, maple, acacia, mizunara and cherry to infuse their whiskies with distinctive notes and aromas. In general these are used for finishing spirit already matured in oak casks, but full maturation examples of the same do exist more commonly coming from independant bottlers.

In addition to the type of wood, the previous contents of the cask can significantly influence the final product. Distillers often seek out casks that have housed different fortified wines (such as PX, beers, or spirits to introduce new dimensions of flavor to their whiskies.

Maturation and the Scotch Whisky Association

It is important to note that the Scotch Whisky Association imposes strict regulations on the types of casks used in Scotch whisky production. According to their rules, the spirit must be matured in new oak casks or in oak casks that have only been used to mature specific types of wine, beer, or spirits, maintaining the traditional characteristics of Scotch whisky. Despite these restrictions, the recent expansion of the rules has allowed Scotch whisky to be matured in casks previously used to age a wider variety of spirits, including agave spirits, Calvados, barrel-aged cachaça, shochu, and baijiu, opening up new avenues for flavor exploration.

Finished bourbons

In the American whiskey landscape, the phenomenon of barrel finishing is relatively recent compared to its long-established practice in Scotch production. The core of this difference lies in the stringent definition of bourbon, which mandates maturation in new charred oak barrels without the introduction of any additional flavoring or coloring.

However, distillers have navigated this rule by introducing a process where, after the initial aging in new charred oak barrels, the bourbon is transferred to different casks for finishing, such as sherry casks. This process technically transforms the bourbon into a “whisky specialty,” more commonly referred to as “finished bourbon.” It is essential to note that bottles resulting from this process are labeled as “whiskey” rather than bourbon to adhere to the regulatory definitions while still offering a product with a rich, nuanced flavor profile derived from the finishing process.

Types of Wood Used in the Whisky Production Process

While the use of oak remains supreme in the whisky production process, a variety of other woods have found their place in different stages of production, including in the creation of casks, washbacks, and even mash tuns. These woods not only play a pivotal role in the maturation of whisky but also influence the intricate flavors, aromas, and colors that are characteristic of different whisky varieties.

1. Oak

• Usage: Essential for whisky maturation. Used for casks and finishing.

American White Oak (Quercus Alba)

• Usage: Used for Bourbon barrels and some sherry casks.
• Characteristics: Imparts vanilla, coconut, and sweet spice aromas.

Spanish/European Oak (Quercus Robur)

• Usage: Common for sherry casks.
• Characteristics: High in tannin and gives aromas of dried fruit, clove, and resin.

Sessile Oak or French Oak (Quercus Petraea)

• Usage: Used by the Cognac industry and now in Scotch and Japanese whisky.
• Characteristics: High in tannins and spiciness.

Mongolian Oak (Quercus Mongolica)

• Usage: Rare and expensive. Used in Japanese whisky production.
• Characteristics: Gives fragrant aroma of incense, sandalwood, pineapple, and coconut.

Mizunara Oak (Quercus crispula)

• Usage: Often used for finishing rather than full maturation in Japan.
• Characteristics: Unique sweet and spicy taste profile with aromas of Kara (oriental incense), sandalwood, and coconut.

Garry Oak (Quercus garryana)

• Usage: Rarely used; native to the American Pacific Northwest.
• Characteristics: Used in experiments by Seattle’s Westland Distillery, resulting in a creamy whiskey with dense fruit flavors and spiky spices.

2. Amburana Wood

• Usage: Primarily used in South America for aging cachaça and rum.
• Characteristics: Imparts unique flavors like cinnamon, nutmeg, and tropical fruit.

3. Alternative Woods

• Usage: Used for special barrels to impart new flavors.
• Types: Canadian white oak, cherry, beech, ash, hickory, chestnut, and Japanese cedar.

Cherry Wood

• Usage: Recently utilized by distilleries such as Teeling and Mackmyra for aging whiskies, showcasing a trend of experimentation with this wood type. Teeling, for instance, used it for a 15-year-old Irish Single Malt, initially aged in bourbon barrels and then finished in virgin Cherry Wood casks.
• Characteristics: More porous than oak, allowing for a quicker finishing period and an unusual flavor profile. It imparts floral notes, dried fruits, and mellow spices, with aromas of wood spice, brown sugar, prunes, raisins, and sultanas. It offers a taste profile with notes of sawdust, sandalwood, rosewater, and Turkish delight, with a long finish of mellow spice.

Chestnut

• Usage: Although not a common choice for whisky maturation, it has been used by some distillers looking to introduce a different range of flavors into their whiskies.
• Characteristics: Chestnut wood is known to impart spicy flavors such as nutmeg and cinnamon, along with herby and woody notes. It tends to have a higher permeability compared to oak, which can result in a more significant influence on the whisky in a shorter period.

Japanese Cedar

• Usage: A rare choice in whisky production, but it has been explored in the Japanese whisky industry to bring unique characteristics to the spirit.
• Characteristics: Japanese Cedar wood is known to introduce sweet and smoky flavors, reminiscent of Mezcal, into the whisky. It adds a distinctive aromatic profile, bringing a fresh and somewhat floral note to the whiskies, offering a different dimension to the tasting experience.

4. Douglas Fir

• Notes: Also known as Oregon Pine.
• Usage: Primarily used for the creation of washbacks (fermentation containers).

5. European Larch

• Usage: Primarily used for the creation of washbacks (fermentation containers).

6. Unusual Cask Types

• Usage: Distillers use a variety of unusual casks to create unique whisky flavors.
• Types:
  • Port Casks: Impart fruity berry flavors and peppery oak notes.
  • Bordeaux Wine Casks: Add sweet toffee, summer berries, and toasty oak flavors, bringing a touch of French finesse to the whisky.
  • Tequila Casks: Introduce sweet, peppery notes with a tropical vibe.
  • IPA Casks: Enhance the whisky’s citrus notes.
  • Rum Casks: Add extra caramel sweetness and creamy vanilla flavors.
  • Cognac Casks: Introduce a hint of sweet banana to the whisky flavors.