Truth and Misconceptions about Sherry Casks
Basics and background of "Sherry Cask" that whisky lovers should know
[Introduction]
The term sherry cask aging is an essential part of any discussion of the appeal of whiskey. However, the true nature of this process may be surprisingly unknown.
In this article, we will provide a neutral view on the nature and origin of aging casks known as "sherry casks", as well as the variety of sherry casks currently on the market, while organizing basic information.
1. The relationship between whiskey and oak barrel aging
- Oak barrels play an important role in adding, absorbing and changing the flavour of whiskey.
There are four main processes thought to occur in whiskey during barrel maturation:
- Additive effects: Compounds released from the oak add aroma and flavor. These include aldehydes, lactones, lipids, and tannins.
- Subtractive effects: The carbonized inner wall adsorbs impurities and regulates the flavor.
- Interaction: The whiskey and oak combine chemically to create new compounds.
- Oxidative effects: The influx of small amounts of oxygen causes the flavor to mellow over time.
These are basic principles that apply not only to sherry casks but to all oak casks.
2. What is Sherry? - Understanding the Solera System
Sherry is a fortified wine produced in the Andalusia region of Spain, and undergoes a unique aging process called the "solera system."
The solera system is a method of stacking multiple barrels in layers, bottling wine from the bottom level and then refilling it from the top level.
This process is repeated every year, constantly blending young and old wines to ensure a homogeneous and balanced ageing.
In addition, in types of sherry such as Fino and Manzanilla, the "flor" (yeast film) covers the surface of the barrel and plays a role in preventing oxidation, while in types such as Oloroso and Pedro Ximenez, oxidation progresses, resulting in a richer, fuller flavor.
As you can see, even though they are all sherry, the maturation conditions and styles vary greatly, and the impact they have on whiskey is not uniform.
3. The spread and misunderstanding of the term "sherry cask"
Many of today's "sherry casks" are different from the barrels that were once used to age wine for long periods of time.
When it comes to whiskey, the term "sherry cask" originally referred to barrels that had been used for long-term sherry aging.
However, nowadays, there are many "seasoning casks" on the market that are newly made specifically for the purpose of maturing whiskey and are filled with sherry for a short period of time, and it is said that there are differences in flavor and sense of maturity.
In particular, in the whiskey industry, it is difficult to obtain a stable supply of "genuine solera barrels" that are actually used in the solera system, so it is not uncommon for wineries to contract with each other to procure special barrels that are intentionally used to "transfer the sherry flavor."
These seasoning casks are sometimes given technical treatments that prioritize marketability, such as re-firing the inside of the cask or using concentrated sherry, to intentionally impart a strong flavor even with a short aging period . This can result in a "well-balanced aroma" or "monotonous sweetness" that is different from the sherry aroma of the past, which was achieved by natural aging.
4. Historical Background: What were "Real Sherry Casks"?
Before the 1980s, when sherry was transported to the UK in barrels, the actual aging barrels were converted into whiskey.
At that time, sherry produced in Spain was transported in barrels to Scotland and used directly to age whiskey.
Sherry casks from this period are said to have been a mixture of what we now call "solera casks" and "transport casks", and the type of oak used was sometimes different to that used today.
However, after legal changes in 1986, restrictions were put in place on the transport of barrels from Spain, making it said to be difficult to obtain authentic Solera barrels.
Many of the sherry casks from this period were genuine casks that had been used in the Solera system for many years, and are said to have given the whiskey a special depth and complexity of flavor. The reason why some whiskeys bottled before the 1980s are highly regarded as "ideal sherry cask aging" is thought to be due to these differences in actual aging history.
5. Current Trends: The Role of Seasoning Casks
Many modern sherry casks are “reused casks” purposely made for whiskey.
In recent years, wineries have begun to custom-make "seasoning casks" for the whisky industry. These casks are delivered to the whisky distillery with the wine already infused with flavor after a relatively short period of time.
Today's seasoning casks can be thought of as "sherry casks for whiskey" designed for flavoring purposes.
On the other hand, the sherry barrels that were once used actually aged wine for many years, and it is said that the aromatic compounds that were naturally developed during the aging process permeated the barrels.
Therefore, even if they are both labeled as "sherry cask," it is said that there are clear differences in the flavors obtained.
In this respect, whiskey matured in sherry casks in old bottles bottled before the 1980s is likely to have been made in casks that had actually been used to age wine over a long period of time , and is said to have a deeper sense of maturity and lingering aftertaste that is different from that of seasoning casks. The unique appeal of these bottles is one of the reasons why they are still popular with collectors and enthusiasts today as "old sherry."
6. Management and localization of the name "Sherry"
The name "Sherry" is protected by the EU's Protected Designation of Origin system, and there are strict rules regarding its use.
The name "Sherry" is only allowed to be used for fortified wines produced in limited areas of Spain, such as Jerez and Sanlúcar.
Therefore, wines aged in other regions, or products of a similar style, cannot be called "Sherry".
In this way, when using the term sherry cask, we believe it is important to determine how close the wine and production methods used for maturation are to "original sherry."
7. Summary: The discrepancy between the impression of the words and the actual flavor
We believe it is important to enjoy the unique characteristics of sherry casks while understanding the “gap in expectations” between labeling and reality.
For many consumers, the term "sherry cask aged" conjures up images of a mellow, rich aroma. However, the effect that the casks have on the whiskey varies greatly depending on the process they went through and how long they were used.
For this reason, we do not judge sherry casks based solely on the one-dimensional impression that "sherry casks = luxury/exclusive," but rather we believe it is important to understand the flavor trends and carefully enjoy each and every bottle.
In particular, old bottles from before the 1980s may have been aged in sherry casks that had been used for a long time to age wine , and the depth and lingering aftertaste of these casks tend to be highly valued as something that sets them apart from modern products. By understanding the difference between these casks and modern seasoning cask products, you can enjoy them in a more multi-layered way.
Sherry casks are wonderful for adding depth to whisky, but there is a lot of diversity in their backgrounds and realities.
The contents of this article are merely our company's opinion and are not definitive. We hope that it will be of some help when choosing whiskey in the future.