First Fill Second Fill Barrels
In conversation with Master Distiller Binyomin Terebelo of Terebelo Distillery on what goes into designing a release and what he does for clients privately.
Whisky is aged in oak casks that have a lifetime of 70 years. This means a barrel is used more than once. A barrel the first time used is referred to as the first fill. This means a 12-year aging period before the cask is emptied and filled with new make spirit for a second time, referred to as a second fill. Barrels may be filled a third or even fourth time.
Each fill has a different influence on the flavor of the resulting malt whisky, which means the fill is a significant factor.
Casks have previously been used to age bourbon or sherry, with each type of cask contributing different flavors to the maturing malt whisky. Bourbon barrels add, for example, vanilla and a light sweetness, while sherry casks lend richer sweetness with a range of fruit cake and dried fruit notes.
The Number of The Fill Cask Influences Every Fill
Each time a standard cask is filled, the influence of the oak on the maturing malt whisky is reduced.
- A first-fill bourbon barrel is used to age malt whisky for 12 years.
- A second time and used for a further 12 years, the influence of this barrel is typically around 25 to 30 percent compared to the first fill.
- The influence of a third fill, another 12 years, would be around 10 percent of the first fill.
Sherry Casks First And Second Fill As Well As Other Finishing Barrels
- The second fill of a sherry cask typically has an influence of around 50 percent compared to the first fill,
- with a third fill approximately 15 to 20 percent,
- and the fourth fill is around 10 percent.
The influence of a sherry cask doesn’t reduce as rapidly as a bourbon barrel because they have a higher level of flavor compounds than bourbon barrels when they arrive in Scotland.
One reason is that sherry casks are used initially to age sherry, which has a strength of only 17% ABV—in comparison, bourbon barrels are filled with a spirit, up to a maximum strength of 62.5% ABV, in order to produce bourbon.
A higher strength spirit is more ‘active’ while aging in a cask than sherry and extracts a higher level of flavor compounds from the oak.
Note the Difference Between First And Second Fill Bourbon And Other High Alcohol
Successive fills aren’t simply a ‘milder’ or ‘diluted’ version of the previous fill, as each fill also delivers a slightly different version of the same flavors. Vanilla, a hallmark of aging in bourbon barrels, is a prime example.
“The level of vanilla gained from 12 years of aging in a second fill would be lower and different from that gained from 12 years in a first fill. The vanilla notes from a second fill would have a more caramel character and not be as rounded or honeyed as the vanilla notes from a first fill.
Note the Difference Between First And Second Fill Sherry and Other Wine
Similarly, the archetypal fruit notes contributed by a sherry cask change from one fill to another.
A first fill gives a really rich fruitcake and fruit notes like raisins. A second fill delivers distinctive fruitcake notes, which are not as dominant as the first fill, while the fruits are more prunes, dates, and stewed fruit.
In addition to individual flavors evolving in each fill, the overall balance of flavors also changes. The character of the new make spirit aging in the casks, for example, can be more prominent in subsequent fills.
During the first fill, the character of the new make spirit is, to a certain extent, ‘masked’ by the intensity of flavor compounds contributed by the cask. However, as second and third fill casks deliver a lower level of flavor compounds, this allows the original character of the spirit to show through more clearly.
Oxidation is the result of air passing in and out of a cask. During this process, air dissolves into the spirit (oxygen is the key element), which initiates various reactions, typically resulting in the spirit becoming fruitier, more balanced, and gaining complexity. Similarly, the effect of oxidation can show more clearly in a second and third fill cask compared to the first fill due to the lower level of flavor compounds coming from the barrel.
Meanwhile, how many times an oak cask can be filled, and the result that each fill will give is hardly guaranteed. After all, oak is a natural product; barrels can show significant variations. The only way of knowing how a cask has performed and whether the cask is capable of another fill is to analyze the mature malt whisky when a barrel is emptied.
There is a lively debate among connoisseurs about the merits of drinking the first cask vs. second cask single malt whiskies in terms of their quality, strength, taste, and flavor. There is also solid scientific evidence – backed up by the actual taste – that there are significant differences in certain types of casks and how first, second, and third fill whiskies taste.
Your taste your passion, reach out today to, Binyomin at 5512387791 or via email at email@example.com