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.

Tasting at Highland Park

I participated in a tasting of seven whiskies at Highland Park Distillery on April 22^nd 2014. The whiskies were the standard 12Y, 15Y, 18Y, 21Y, 25Y, 30Y and a 46Y cask sample of an American oak cask from 1968.  Highland Park is matured in sherry casks made of European and American oak. Some independent bottlers mature in bourbon casks. The Highland Park whiskies have a light sweet heathery smokiness about them, quite different from the wood flavour typical for Islay whiskies.

Highland Park is malting 20% of their malt on site. 80% is sourced from Simpsons.

Highland Park stores 80% of their whisky on site, while 20% is stored in the Glasgow area. The finished product has the same 80-20 mix. The oldest cask in the warehouses is more than 100 years old, and the oldest whisky in store is 56 to 57 years old.

The 12Y is a nice whisky with a pronounced sherry flavour by its own, but compared with the others the new make is overpowering the whisky. The 12Y has some vanilla and cinnamon.

The 15Y is light fruity and floral on a bed of vanilla. It’s the one closest to the 46Y in flavour.

The 18Y is like candy with a delicate combination of stewed fruit and floral notes. I got a dry aftertaste with light coco at the end. This is good value for money.

The 21Y is back at 47.5% with the 3^rd filling, after a visit at 40% in the 2^nd filling. Approximately 10% of the whisky is 30 years old and 10% 40 years old refill. The rest is 40-50% first fill. The 21Y has sherry nose with linoleum in the background and a dry finish.

The 25Y is a round balanced whisky with pronounced sherry nose. It has a floral and candy like background with a light dry aftertaste.

The 30Y is matured in 100% refill (2.fill and 3.fill) sherry casks. It is round and balanced with sherry, stewed fruit, candy and vanilla on the nose, with a dry aftertaste.

The last whisky was av 46 years old cask sample from a second or third fill American oak cask filled in 1968. It’s extremely round and balanced with vanilla and candy character, and some sherry and oak in the background. It is the best of the whiskies, but not commercially available.

Type	Alc.	Eur. wood	First fill	Colour	Sherry	Fav.
12Y	40%	80%	15-20%	2	5	7
15Y	40%	40%	20-25%	3	2	6
18Y	43%	80%	45%	4	3	4
21Y	47.5%	20%	15%?	5	3	4
25Y	45.7%	80%	50%	5	6	3
30Y	48.1%	80%	0%	7	7	2
46Y	40.1%	0%	0%	1	1	1

In the table, colour is ranged from light to dark and sherry flavour from light to heavy.
The percentages of European oak and first fill is not confirmed and is to be regarded as work in progress.

I tried, Harald, one of the travel retail whiskies in the Warrior series last night, and compared it to the 18 year old. They are priced at the same level, but there is a huge difference in quality. The 18Y is fruity, floral and candy like, while I find Harald to have a pronounced nose and flavour of decay. I find Harald to be just one more NAS whisky contributing to destroying the reputation of Scotch, but there are worse NAS whiskies out there.