Lesson 08: What types of wood can be used for ageing whiskey?

If you have made it this far, you will know that almost all types of American whiskey products (more than 99%, based on volume) have been aged in wooden barrels. By law, the barrels must be made of oak. I am not sure that this rule applies to whiskey producers globally, but in the United States it is the rule.

And why is that you may ask?

As it turns out, oak has some amazing properties that make this sort of wood ideal for storing whiskey – and that is the reason why its use is governed by law. One of these properties is the incredibly dense molecule structure. When the molecule structure is dense, it is more difficult for the liquid in the barrel to leak out and/or evaporate. And that is obviously very important 😊

Even though the law stipulates oak as the only approved type of wood, it does not specify which type of oak, so you are free to use any type of oak (there are more than 500 known types). There are, however, significant differences between the individual oak type’s ability to hold the liquid.

As an example, watch this mind-blowing video where you can see the differences between white oak and red oak’s ability to hold liquid:

Most whiskey manufactures use American White Oak (Quercus Alba), but French Oak (Quercus Robur) and Irish Oak (Quercus Petraea) can also be seen from time to time. Sometimes, you can read on the label, which type is used.

So … I have read something about cherry wood barrels – what is that all about?

Well, if you have heard about this in connection with whiskey production, there is actually some merit to this; It IS allowed to use non-oak barrels, as long as the barrel is a “finishing” barrel. A finishing barrels is a barrel you use for a second ageing process, AFTER the normal ageing in an oak barrel. The whole finishing concept is used to add special flavor to the whiskey and will be explained in an upcoming lesson. Typically, finishing barrels are used port, sherry, or rum barrels (which also uses oak) – but occasionally they are barrels made by non-oak wood types. The most common types are cherry and acacia.

And that concludes this lesson.

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