Not all Casks are Created Equal

Within the realm of Scotch whisky, there exists a diverse array of casks, each with its own distinct characteristics and contributions to the spirit’s flavour profile.

The most prevalent type of cask in the Scotch whisky industry is the re-fill ex bourbon
barrel, accounting for approximately 90% of all whisky casks. These barrels, typically 200 litres in size, are often shipped from the United States and reassembled in the UK.

Some are rebuilt as hogsheads, which have a capacity of 225 litres, although they have become increasingly rare. Another popular cask type is the ex-sherry cask, either rebuilt as hogsheads or reassembled as sherry butts, which have a capacity of around 500 litres. Additionally, various other casks previously used to age different liquids such as Port, wine (both red and white), fortified wines like Banyuls or Sauterne, and even other spirits like Cognac, Armagnac, or tequila can be found. Casks that deviate from the ex-bourbon barrel or ex sherry cask norm are considered more unique and less common.

In addition to the size and the previous liquid held within, the number of times a cask has been used is also a significant factor. A cask filled with Scotch for the first time is referred to as a “1st fill,” while subsequent fillings are known as “re-fills.” Although less commonly specified, some casks may indicate their number of fills, such as “2nd” or “3rd fill.” It is worth noting that while the number of fills can be important, the length of time the cask previously held Scotch is often more crucial, even though this information is seldom available.

The type of oak used in crafting the cask also plays a pivotal role. American oak imparts a distinctly different flavour profile compared to European oak, and even within American oak, there are different varieties. Moreover, there are rare types of oak being utilized, such as Mizunara from Japan and even Scottish oak, which possesses a peppery flavour profile distinct from other European oak varieties.

These differences in casks have a profound impact on the resulting whisky, making them of great significance not only to independent bottlers but also to investors.

When considering the purchase of a cask, two primary factors come into play: the
investment amount and the desired duration of the investment. For long-term holdings,
such as twenty years, re-fill casks are generally considered safer as they are less likely to overpower the spirit over an extended period. Conversely, for shorter investment periods, like five years, a 1st-fill cask may be more suitable, depending on the whisky’s age at the time of purchase.

The second consideration is the age of the cask at the time of purchase. Whisky undergoes significant maturation periods, with twelve, eighteen, twenty-one, and thirty years being notable milestones. It is crucial to understand that not all whiskies age gracefully. For instance, Springbank is generally exceptional only up to thirty years old, with most bottlings needing to be sold well before reaching that age. Other distilleries’ spirits, however, can age much longer. Once a cask has reached its peak, it cannot be reversed, rendering all the time and effort invested in it wasted should it go over the peak. These “overmature” whiskies are typically blended away, used to add depth to blends, and when sold as blending components, their value is significantly diminished.

In some cases, a cask may contribute little to the whisky, even after many years, resulting in a spirit that appears youthful and lacks colour. This is not a disaster, as it is possible to enhance the spirit by transferring it to a different cask. This process, known as re-racking, has the potential to transform the whisky. Many of the whiskies we enjoy today undergo a finishing period in a second cask before bottling, which serves a similar purpose. The cask may spend most of its life in an ex-bourbon barrel but then spend a few months or years in another cask, such as an ex-sherry or wine cask, to add additional flavour before being bottled.

Ultimately, there are some basic guidelines to consider. For those seeking to own a cask for an extended period, a 1st-fill sherry butt may not be the most suitable choice, while a re-fill hogshead (ex-sherry or ex-bourbon) would likely be more appropriate.

Think of casks as inverted tea bags: a new teabag imparts strong flavour quickly but
steeping it for too long results in an overly tannic and undrinkable cup of tea. Reusing the same teabag imparts flavour more slowly and never reaches the same level of tannic bitterness. Similarly, when deciding on the duration of cask ownership, it’s helpful to consider these dynamics.

Ultimately, all whisky should find its way into a bottle. If a cask reaches maturity sooner
than expected, to hold value, it should still be bottled. Conversely, if a cask remains
youthful, re-racking can still yield a remarkable whisky.