Flavour From Oak

As previously highlighted, not all casks are the same except in Scotch whisky except they are all made of oak. Varieties of oak vary all over the world and have very different flavour profile characteristics.

In this article I want to concentrate on the characteristics of the oak variety rather than any previous contents the cask might have held, which will become the subject of a future article.

Not only are there variations in oak from country to country, but also variations within the same country. Large countries like the USA, have such varying landscapes and climate that the oak grown in the northwest, is quite different to that grown in the deep south.

The two main types of oak are European, or Quercus Robur, and American Oak, Quercus Alba. The former grows with a tighter grain and tends to grow very straight. European oak is usually wider, and not so straight. These two have the most obvious differences in flavour profile. The American oak tends to have sweeter flavours and the European oak tends to have spicier flavours.

There are species in the USA which can also present a spicy note, but also the sweeter flavour profiles. Chinkapin oak, or Quercus muehlenbergii grown in most inland areas of the US with the and used by distilleries like Teeling in Ireland and Raasay in Scotland has this sweet profile with a spicy edge or back palate. This, depending on the spirit and the blend of casks can give greater depth to a whisky without the spicy nature becoming dominant. Another American oak type grown in the Northwest is Garryana, Quercus Garryana, and is used in an expression by Westland distillery from Seattle to create an aromatic whisky with notes of cloves and baking spice which is not normally found in Quercus Alba American oak matured whisky.

In Europe the two cask types with distinctive flavour profiles are Spanish and French oak, Quercus pyrenaica and Quercus Robur. French oak comes from 5 main areas Allier, Limousin, Nevers, Trincais and Vosges. Each of these areas produces an oak with slightly different characteristics, but all are aromatic with lifted spices as the oak has a very tight grain and is very sought after in wine making and has a great effect on whisky maturation if ex wine casks are being used. Hungarian oak is also used, and in very small amounts, Scottish oak is not even used. The later tends to grow very awkwardly with many knots making it difficult to cooper, and also has a pronounced peppery spice which takes careful blending but giving Scottish oak matured whisky a unique characteristic.

Another rare type of oak which is highly sought after and extremely expensive is Mizunara, Quercus Crispula. Found in Japan this oak has a different flavour profile of lighter spices, and a Korean herbal incense called Kara Young, and a Japanese spicy paste called Yuzu Kosho. This oak is used often in the ends of casks to give extra flavour and lift without being overpowering.

All of these types of oak will react differently with spirit depending on the nature of the spirit and if there has been any other liquid filled into the cask before the introduction of whisky.

Author: Colin Hampden-White