Friday, 30 December 2016

Sherry casks

Traditionally the whisky industry uses transport casks for sherry cask maturation. The transport casks are more active than the solera casks that are used for years and mainly removed when they start to leak. In 1981 it became illegal to export sherry in casks. Today transport style casks are produced primarily for the whisky industry.

Fino has a dry style that is nutty and yeasty. The colour is light. Fino is almost always matured in American oak casks.

Oloroso is rich and complex with residual sweetness. When adding grape spirit to 17% the yeast is killed and will not build a protective layer as in the 15% fino process. The Oloroso is rounded and darkens due to oxidation.

Pedro Ximenez is made of dried grapes, almost raisins, and is pressed into a very sweet liquid. PX is used to sweeten the Oloroso made for the British market.

The sherry producers have used mostly American oak for the last 200 years. European oak casks are made by special order for Edrington, Glengoyne and G&M.

European oak used for sherry production is mostly sourced from places like Galicia, Asturia and Cantabria in northern Spain. Quercus Robur from Galicia gives a spicier product with notes of cinnamon, nutmeg, dried fruits, candied peel, caramel, orange and Christmas cake, chocolate and wood. American oak has more flavours like vanilla, honey, coconut, almonds, hazelnuts, butterscotch, fudge and ginger.

Edrington cooperates with the cooperages like Tevasa, Vasyma and Hudosa who turn trees into casks. The casks are filled with Oloroso for 18 months. Edrington cooperate with bodegas like Gonzalez Byass and Willams & Humbert. They use different cask sizes like butts, puncheons and hogsheads.

Both butts and hogsheads are made of American and European oak. That is, butts are not synonymous with European oak, and hogsheads are not synonymous with American oak.

When it comes to single cask whiskies, the type of cask is generally written on the bottle. The whisky should in general be matured in the same cask for the whole maturation, but it is no guarantee. In a worst-case scenario, whisky could have been transferred from one or more casks to a new cask, which is described as the single cask. Some reasons for transferring whisky could be cask leakage or that the whisky is not maturing well.

The Edrington distilleries Macallan and Highland Park both predominantly matures their whiskies in sherry casks, but Macallan is generally known for a heavier sherry influence than Highland Park. How can this be, when they have the same Edrington cask source?

After talking to the Edrington ambassadors Sietse Offringa and Martin Markvardsen, I conclude that Macallan has an oilier spirit that is more active extracting colour and flavour from the casks. In addition, Macallan probably uses more active casks, that is first fill casks, than Highland Park. The ratio between American and European oak sherry casks is more likely the same. The climate influence is probably minuscule, even though larger temperature variations in general results in increased wood extraction.