Introduction Malting Grinding Yeast Distilling Ripening Filtration Bottling
Phase 5 - The Maturation
The distillate is stored in oak barrels. Use is made of oak barrels previously used for American Bourbon and Spanish Sherry. The distillate with an alcohol percentage between 65% and 70% must legally mature for at least 3 years to be called Scottish Whiskey.
While ripening, the taste of the whiskey is combined with the natural substances contained in the oak barrels. In the end, every whiskey gets its own taste and smell.
Because the barrels are burned to a greater or lesser extent on the inside and the tannin in the wood gives the whiskey its caramel and vanilla flavors. If Spanish Aloroso sherry barrels are used, the taste of the sherry will also influence the final whiskey taste.
Color of the Whiskey
Whiskey that has matured only in ex-sherry barrels does not have the vanilla / caramel flavor like the whiskey that has matured in ex-bourbon barrels. The whiskey is therefore drier in taste. The barrel of European oak gives darker colored whiskey than an ex-bourbon barrel. The color comes from the tannin in the wood and not from the dark Aloroso sherry that has matured in the barrels before!
The dark color of the whiskey also has nothing to do with the charred layer of wood on the inside of the barrel. This has the Bourbon that previously matured in it gave the caramel taste. The ex-sherry barrels are less roasted (English: charred) but therefore give much darker colored whiskey.
The longer the whiskey matures in a barrel of European oak, the darker the whiskey becomes. Often a combination is also used. The whiskey first ripens for 8 years in ex-Bourbon barrels and then for 2 or 3 years in ex-Sherry barrels. This will make the taste more complex.
Wood is naturally porous and will breathe. As a result, characteristics of the air from the environment are transferred to the whiskey. The location where the whiskey is stored is decisive. If this is on the coast, so in the sea air, or somewhere in the middle of the Highlands, the taste and smell are influenced differently.
Through natural evaporation (English: evaporation) 2% of the drink is lost annually. This is also referred to as the angel's share. Partly a reason why old whiskey is more expensive than its younger years.
The European oak is less porous than the American oak and therefore better suited for a longer maturation of the whiskey. However, it is also true that as a rule an ex-Bourbon vessel has a capacity of 200 liters and an ex-sherry vessel has a capacity of 500 liters. The smaller the barrel, the faster the maturation proceeds. The contact surface of small vessels is relatively larger.
Whiskey is "always" matured in used ex-Bourbon or ex-Sherry barrels (there are exceptions). The whiskey maturing for the first time on the used barrels is called maturing on "first-fill" barrels (English: maturation on first-fill casks). In total it can be used a barrel 4 times before it is "exhausted". In the second, third and fourth maturation, one speaks of maturing in "re-fill" vessels.
With quality whiskey only "first-fill" barrels are used. This must therefore be stated on the label.
Next phase: FILTRATION