What is an Oloroso Sherry Cask (whiskey)?

What is an Oloroso Sherry Cask (whiskey)?

Where do Oloroso sherry barrels come from?

Oloroso sherry barrels always come from Spain. More precisely from the area around the city of Jerez de la Frontera, in the south of the Iberian Peninsula. The different sherry wines can only be produced in the so-called "sherry triangle".

What is Oloroso sherry?

Sherry is generally a fortified white wine. Oloroso is a sherry a oxidative maturation obtained from palomino grapes. This type of sherry is typically full-bodied, strong and dry, but is sometimes sweetened by adding other types of sherry. 

The properties of the Oloroso sherry are transferred to the cask and subsequently to the whiskey.

Why is whiskey aged in Oloroso sherry casks?

Thanks to their harmonious character, Oloroso barrels are very popular for whiskey maturation. 

The taste of Oloroso sherry marries elegantly with the aromas of whiskey in most bottlings, but is not too dominant. In this way, Oloroso sherry casks can add more flavor to a bottling expanding the taste-olfactory profile of whiskey.

Oak barrels of other types of sherry, such as Pedro Ximénez, are also used to mature the whiskey. However, Oloroso barrels are less sweet and flavorful than Pedro Ximénez barrels.

There are different types of ex sherry aging:

• Un whisky “Sherry Oak” it is stored in sherry barrels for the entire duration
• Un single malt “finished in Sherry cask” it often matures initially in ex-bourbon barrels and then completes its aging in sherry casks (e.g. Olrooso cask) for a few months.
• I “Double matured”, part of the whiskey is stored in ex-bourbon casks, another, for example, in Oloroso sherry casks. Then there is the assembly of the two together.

How big are Oloroso sherry barrels?

With a volume of 500 liters, Oloroso sherry barrels are significantly larger than traditional ex-bourbon barrels, which only hold 225 to 250 liters.

A whiskey (but also a wine, a rum or any other alcoholic liquid) it tends to mature more slowly in larger barrels, as a relatively minor amount comes into contact with the barrel surface.

However, not all sherry cask whiskeys are actually stored in 500-liter barrels. Upon request, bodegas also produce hogshead sherry in desired specifications, which can then be placed alongside bourbon barrels of the same size in Scottish warehouses.

For the production of the sherry barrels it is possible to use European and American oak wood. The term "aged in Spanish oak barrels", which can be found on some whiskey bottles, refers to the manufacture of the barrels in Spain, but not to the origin of the wood or the type of oak.

What is the contribution of Oloroso sherry to whiskey?

Oloroso sherries are dry, strong and full-bodied in their character. Whiskeys that have been aged in former Oloroso sherry casks are mostly characterized by fruity, woody and ripe aromas. 

The respective flavor profile it also depends on the duration of maturation, by intensity (first fill, second fill) e from the quality of the barrels used.

Typical of the whiskey aged in Oloroso barrels is a dry, but also soft and full flavor. Concise notes that can be discovered in Oloroso barrel-aged whiskey are dried fruit such as figs, plums and raisins. Fruit notes are often complemented by distinctly spicy oak notes.

Among the main Scottish distilleries that use Oloroso sherry casks we find Glenfarclas, Mortlach, Glenfiddich, Dalmore e Glenmorangie.