There are plenty of resources out there explaining how Scotch whisky goes from new-make spirit to full-fledged Scotch via maturation in casks (I’ll include some links at the bottom of this post). However, I decided to go ahead and do a blog post that pulls together some of that information. More specifically, I want to point out and discuss areas where I often see confusion and debate even amongst whisky enthusiasts. Hopefully I’ve got this down, but I’m open to correction if I’ve screwed anything up.
Scotch whisky, after being distilled, must be matured for at least 3 years in oak casks before it can officially be called Scotch. It’s right in the Scotch Whisky Association regulations. American oak (Quercus alba) and European oak (Quercus robur) are the most common species used for cask creation. Additionally, most Scotch whisky casks were previously used to mature bourbon or sherry. On a lesser scale, there are other types of previously used casks, such as Rum, Madeira, Port, Tokaji, and other wines. These are often used to “finish” a whisky after its initial maturation in sherry or bourbon casks, but can also be used for the full maturation period. Springbank 11 year “Madeira Wood”, for example, was matured entirely in ex-Madeira casks.
It’s all oak!
This brings me to the first point of confusion that I’ve witnessed. American oak bourbon barrels are the most common source for Scotch whisky casks. I’m not sure where it started, but it’s common to see the term “traditional oak” used to describe a whisky matured in ex-bourbon casks. I think in conversation, this sometimes gets shortened to “oak.” Now you have people talking about whether the whisky was matured in sherry or oak casks. Oak becomes a synonym for an ex-bourbon, American oak barrel. That’s very misleading.
All of these casks (bourbon, sherry, madeira, etc.) are made from oak. The maturation differences come down to type of oak, whether the wood on the inside of the barrel was charred or toasted, and what kind of (if any) liquid was previously matured in it. Scotch casks can also be re-used, which becomes another factor in the flavor and color profile of the whisky.
Update: Immediately after posting this, I saw a tweet advertising Black Bull 12 Year, along with the claim “Matured in oak.” This is the kind of lame marketing that adds to the confusion. Stating this on the bottle or marketing literature would seem to imply that it could have been matured in something else. Doesn’t it just make them come across as looking either dumb or condescending, and not like somebody you would want to buy scotch from? I supposed the practice could date back to before oak was called out as the required wood type. However, wouldn’t that at least make it “lazy” marketing at this point in time?
American oak. It’s not just for bourbon.
Myth: All American oak casks previously matured bourbon.
This is point of confusion #2. While it’s true that you can generally assume that a whisky matured in ex-bourbon barrels was matured in American oak, you can’t assume that an American oak cask was previously used to mature Bourbon. American oak is also used to make sherry casks. In fact, Highland Park uses ONLY sherry casks for the maturation of their standard line of whiskies. To adjust the flavors in their expressions, they play with the ratio of American and European oak casks used, as well as the number of times those casks have been refilled.
Stop giving me the stink eye
When I mention that HP only uses sherry casks, I seem to usually get met with a stink eye look. It seems to be very commonly believed that when Highland Park talks of American oak influence on expressions like the 15 year, they’re talking about ex-bourbon casks. However, their web site very explicitly states that they only use ex-sherry casks. I think part of the reason this is hard to believe is that when you think sherry, you don’t think of America. However, keep in mind that using American oak for sherry doesn’t require that the casks were actually made and used in the United States. The wood can be shipped to, coopered and seasoned in Europe.
I actually wondered about this myself. I believe HP when they say they only use sherry casks, but how do they get the quantity of American oak sherry casks that they need? Then I read James Saxon’s blog post about his Highland Park distillery tour. Here’s how his guide explained it to him…very enlightening!
They have the most dedicated wood policy in the industry – £2 million a year on casks and wood management. This is more than the rest of the industry combined. This was the first I’d heard of it. When it comes to wood, it is Glenmorangie which toots its horn the loudest. Well, like Glenmorangie, Highland Park has its own forests in America where they harvest the wood, lend them to the Sherry industry, then bring them back to Orkney to mature Highland Park. There are no Bourbon barrels in the place, just American oak seasoned in Europe in addition to European oak.
Great stuff! I highly recommend reading the rest of James’ Highland Park tour description, and checking out his other distillery tour reviews on the Scotch Odyssey Blog.
Update: Ok, found another source on the HP sherry cask debate…direct confirmation from Gerry Tosh at HP via Jason Debly’s Scotch Whisky Reviews blog in his nice HP 15 Review.
New Oak. Also not just for bourbon.
Myth: Scotch whisky MUST be matured in used casks.
Scotch is almost always matured in used casks, but there are exceptions. There is nothing in the Scotch Whisky Association regulations prohibiting the use of new (or “virgin”) oak casks in the maturation of Scotch whisky. Meanwhile, there ARE regulations stating that Bourbon must be matured in charred new oak containers. I can see where one might assume that a regulation exists dictating used oak on the Scotch side, but that’s not the case. They just choose to go with used casks to get the flavor profile they’re looking for.
Great resources for more information
- Malt Madness Beginner’s Guide – The whole beginner’s guide at maltmadness.com is awesome. For information on casks and maturation, check out Chapter 5.
- Whisky for Everyone – For a quick guide to the types and sizes of casks used to mature whisky, check out this very straight-forward blog post on whisky cask types and sizes.
- whiskywise.com – Here’s a very comprehensive article on whisk(e)y barrels discussing how oak gives real character to the whisk(e)y.
- World Whiskey by Charles MacLean – This physical book is highly recommended, especially for the new whisky enthusiast, and served as one of my sources while writing this blog post. At $16.50 from Amazon right now, there’s no reason not to own this book. [No, my link does not earn me any kind of affiliate money]
- The Balvenie Whisky Academy – The amazing Whisky Academy video series by The Balvenie includes a 10 minute video on Maturation in Module Two (You’ll need to enter your birth date before entering…Doh!). Satisfy your inner whisky geek and check out as much of the series as you can handle.
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