Recently, I’ve come across several intriguing, perhaps even a bit unusual, cask finishes on the scotch whisky scene. By playing around with different cask types and sizes, the Master Blender can create layers of flavours. They can use a range of the same casks, for example, different fills of ex-bourbon, or mix and match a variety of cask types from bourbon to rum. But now they have been extending the secondary maturation to mezcal, Champagne, Amarone and more.
But how far can the industry push it?
The Scotch Whisky Association (SWA) offers specific guidance on which casks can be used to mature scotch whisky:
‘The spirit must be matured in new oak casks and/or in oak casks which have only been used to mature wine (still or fortified) and/or beer/ale and/or spirits with the exception of:
- wine, beer/ale or spirits produced from, or made with, stone fruits
- beer/ale to which fruit, flavouring or sweetening has been added after fermentation
- spirits to which fruit, flavouring or sweetening has been added after distillation
and where such previous maturation is part of the traditional processes for those wines, beers/ales or spirits. Regardless of the type of cask used, the resulting product must have the traditional colour, taste and aroma characteristics of Scotch Whisky.’
Basically, you can age whisky in casks that previously held other spirits as long as the cask maturation is part of the traditional production of those spirits. Currently, gin and cider casks aren’t permitted.
When it comes to the age of whisky, longer maturation doesn’t necessarily mean better quality; there are simply too many factors that contribute.
See my previous article Types of Casks and How They Influence Whisky to learn more about all things casks.
Unique Cask Types
Mezcal
Mezcal casks are made from American white oak and these have previously been used for bourbon production. Funnily enough, ageing is not considered an important part of mezcal production as many producers believe that maturation will take away from the terroir found in mezcal. Therefore, it might not be the easiest cask to find for wider scotch production.
Kilchoman Distillery has released several whiskies with secondary maturation in ex-mezcal casks, with finishes varying from six to 14 months. Dewar’s Illegal Smooth whisky was finished in illegal mezcal casks. The addition of vegetal flavours lends itself to a highball. The most recent release is probably Rock Island Mezcal Cask Edition, which is a blend of island whiskies with a 12-month finish in mezcal casks.
Whisky tasting notes: earthy wood smoke, green pepper, vegetal, zesty
Tequila
There are actually more scotch whiskies finished in mezcal casks than in tequila ones, probably due to the smoky profile of mezcal. Tequila must be aged in oak, although there are no rules about whether it should be new or used or charred. Like with mezcal, most use American white oak that’s previously been used for bourbon or Tennessee Whiskey. These will bring out notes of vanilla, caramel, butterscotch and gentle spice. There have been some movements in the tequila category towards using alternative casks such as sherry, red wine and even scotch. The length of maturation varies from two to 36 months.
Chivas Regal Extra recently released a 13-year-old blended scotch whisky finished in tequila casks. Although there’s a catch. After the 13 years, only a portion of the whisky was finished in tequila casks before being blended together with the non-finished portion. Kilchoman has released an 8-year-old single malt, which spent approximately 8 months in tequila casks.
Whisky tasting notes: pineapple, cooked agave, caramel, vanilla, herbal, bell peppers
Champagne
When a Champagne producer buys a new cask, the first step is to season it to eliminate excess tannins. After seasoning, the casks are sterilised by burning a sulphur candle in the cask. Some Champagne houses prefer to do the full fermentation in the barrel, others use the wood for ageing only. Needless to say, all this will have an impact on the flavours coming from the cask when it comes to maturing whisky in it.
I recently sampled the Ardnamurchan Paul Launois 2021 release and it was absolutely divine, with notes of sponge cake with summer fruits, cocktail cherries and baking spices. The 2022 release has just hit the shelves and I have no doubt it will be a success as well.
Whisky tasting notes: fresh croissants (no joke!), summer fruits, nougat, white grapes, oak
Sauternes
Sauternes is a sweet wine from the Sauterne region, which is a sub-region of Bordeaux. The grape varieties include Sémillion, Sauvignon Blanc and Muscadelle. The wine is aged in oak for on average less than two years, although some winemakers extend the maturation to up to 36 months.
There are quite a few whiskies finished in Sauternes casks. Arran Sauternes Cask Finish has notes of Seville oranges and honey. The palate of Tomintoul 18-Year-Old 2002 is full of sugared almonds, peaches, nectarines and brown sugar. Glenmorangie Nectar d’Or Sauternes Cask also comes with notes of baked stone fruits, wildflower honey, baklava and candied almonds.
Whisky tasting notes: sweet stone fruits, honey, nuttiness, marmalade
Tokaji
Tokaji is a sweet wine made from white grapes. It is produced in the north of Hungary and in the southern parts of Slovakia. The name is legally protected and only certain wines from the Tokaji wine region can officially be called Tokaji or Tokay. The wine can be fermented and/or aged in traditional 136-litre Gönc and 220-litre Szerednye oak barrels, which can be made using two types of European oak: Quercus Robur and Quercus Petraea, the latter being more common.
Glenmorangie Tale of Cake is finished in Tokaji casks to add those sweet cake notes such as marmalade, honey and stone fruits. One of the recent releases is Glasgow 1770 Tokaji Cask Finish, 53% ABV. The nose on this one is full of orchard fruits, sugary sweetness and floral aromas. On the palate you can find tinned peaches, and it’s sweet, fruity and spiced.
Bunnahabhain Fèis Ìle 2022: 2004 Mòine Tokaji is a peated expression finished in sweet Hungarian Tokaji casks. It has notes of smoky vanilla pods, poached pears and crème brûlée.
Whisky tasting notes: floral, honey, poached pears, toffee apples, apricot
Amarone
Amarone della Valpolicella is an Italian wine made using partially dried grapes. The wine is produced in the Veneto region, which is then split into three zones known as Classico (aromatic wines), Valpantena (light and fruity) and Est (rich with higher ABV). Amarone is matured for a minimum of two years but can be aged for up to 10 years in some cases.
This is a fairly dry red wine with rich and complex flavours and velvety mouthfeel. What makes Amarone interesting for whisky makes is the type of cask. Amarone can be aged in casks varying from French and Slavonian oak to cherry, acacia or chestnut.
Arran Amarone Cask is finished in a selection of Amarone wine casks. It has notes of dark cherries, cranberries, baking spices and dark chocolate.
Whisky tasting notes: red fruits such as redcurrants, cranberries, cherries, black pepper and other spices, red wine
Calvados
Calvados is a French apple brandy made in the Normandy region. Cider fruits are smaller than eating apples and they are rich in tannins. The apples that are used for the production are classified into four categories: sweet, sharp, bittersweet and bittersharp, and it is the blend of these that gives the cider its unique character.
The cider is distilled several times before maturation. Calvados is aged in very dark and old oak barrels, although some producers age the spirit first in new oak barrels for around three months to add vanilla notes and tannins. After that it will go into older barrels (some 100 years old) to avoid too much influence from the tannins.
Some recent Calvados finished whiskies include another Bunnahabhain Fèis Ìle 2022 release, 1998 Calvados Cask. The two-year secondary maturation has added apple notes in many forms from apple pie to fresh green apples and toffee apple. Glenfiddich recently released their Orchard Experiment, which is finished in Somerset Pomona Spirit casks. Pomona is an English apple brandy, so not Calvados, although the process is very similar.
Whisky tasting notes: floral, vegetal, plenty of apple
Anything else?
Apart from your classic Oloroso and PX-sherry casks, some producers are using Manzanilla and Fino, for example. You can find several wine styles from Bordeaux to Chardonnay to Moscatel and a range of rums, not to forget the beer casks such as IPA.
I love these cask experiments, some work others not so much, but there is always room for innovation when it comes to the evolving scotch whisky scene.
Have you tried any whiskies with a unique secondary maturation? What is your favourite cask finish?
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