Sherrywood

When was maturation in sherry casks first introduced and why?

Let me start by expanding your interesting question by asking ‘when were the benefits of wood maturation recognised?’ The usual answer to this is the famous quotation by Elizabeth Grant of Rothiemurchus in her Memoirs of a Highland Lady, where she describes sending a quantity of whisky to her father in Edinburgh from her family home in Strathspey on the occasion of King George IV’s visit in 1824: “My father sent word to me – I was the cellarer – to empty my pet bin, where was whisky long in wood, long in uncorked bottles, mild as milk and with the real contraband gout in it”.

Although this is often quoted as ‘the first reference to the benefits of maturation’, my friends Dave Broom and Arthur Motley did some seminal research on the subject for their excellent Whisky Antiquarian blog and discovered that even during the eighteenth century spirits dealers were stressing the benefits of ‘whisky of great age’ when promoting their goods in local newspapers. Arthur also discovered a hitherto unknown Treatise on the Virtues of Whisky by EB MD (a physician), published first in Dublin in 1740, then in Edinburgh ten years later, in which he writes: “Whisky drank too new may hurt; but this is no Objection to the liquid itself, but against the Abuse of it; because whisky may be kept to grow old”.

Although Arthur and Dave did not find any direct references to ‘sherrywood’ in the eighteenth century, there is a significant passage in Charles Tovey’s book British and Foreign Spirits (London,1864), where he writes:

“It is well known that whisky stored in Sherry casks soon acquires a mellow softness which it does not get when put into new casks; in fact, the latter, if not well seasoned, will impart a woodiness, much condemned by the practised palate. In Sherry casks the Spirit likewise acquires a pleasing tinge of colour which is much sought for; this is frequently imitated by colouring, but is not creditable to those who adopt such petty deceptions”.

The sherry casks referred to above were ‘transport casks’, used to ship sherry from Jerez in bulk, typically in 500 litre butts. Some ex-solera casks were used, but they became scarce and very expensive during the 1870s and ‘80s. Their availability depended on the popularity of sherry in the U.K. market, and this declined during the later decades of the 19th century – just at the time when blended Scotch was taking off. Both transport and solera casks were made from White Oak (Quercus alba), either grown in Spain or imported from America, where it was more abundant.

By the mid-19th century new casks were being made - ‘raised’ is the correct term - and seasoned in Scotland, but sherry casks from Spain were esteemed and although some bodegas made seasoned casks to order of whisky companies (as is the case today), there was an increase in ‘home-made’ casks, from timber imported from the U.S.A. and the Baltic.

William Phaup Lowrie was a wine and spirits broker in Glasgow (with the agency for Gonzalez Byass sherry). He was a pioneer of whisky blending and the original supplier of whiskies to James Buchanan of Black & White fame - Buchanan later bought Lowrie’s business and huge stock of whiskies. He is reported to have “revolutionised the cooperage trade by arranging to have staves cut, in the forests of America, to standard sizes… The wine seasoning of casks was his patent [registered in 1882].” The patent was actually for an apparatus which used pressurised steam to test and season casks with a concentrated dessert wine named paxarette – a blend of Oloroso and Pedro Ximenez sherries with vino de color and concentrated grape syrup.

‘Pax’, as it was generally called in the trade, was also used as a colourant by blenders, but its use was banned by the Scotch Whisky Order 1990, since it was deemed to alter the natural flavour of the whisky, and has been replaced by spirit caramel (E150).

Most of the timber coming into the U.K. was shipped from the U.S.A. and from the port of Memel on the Baltic; Quercus alba (American white oak) was preferred by the whisky industry, ‘Memel oak’ Quercus robur (European oak) was favoured by brewers. Formerly located in East Prussia, and now renamed Klaipeda, in Lithuania, Memel stood close to the mouth of the river of the same name, down which rafts of timber were floated from the great forests of Eastern Europe and Russia. True Memel oak was Russian – the top quality ‘Crown Memel Oak Stave’ was reckoned to be “as near perfect as any oak”, but after 1934 became unobtainable and was replaced by Polish oak - which “though an excellent oak, lacked the perfection of Memel” - and during the 1950s by Persian oak.

Until the 1960s sherry transport casks were made from Q. Alba; since then the majority have been Q. robur (mainly Spanish) oak casks. The former were preferred by the sherry shippers: as early as 1948 Manuel Gonzalez Gordon, the head of the sherry House, Gonzalez Byass, commented: “In recent years some Spanish oak has been used [for shipping sherry], due principally to the difficulties of obtaining American timber”. This was confirmed by Alexander Williams of the equally famous sherry house, Williams & Humbert, in conversation with George Urquhart of Gordon & MacPhail, Elgin.

In 1981 Spanish export regulations outlawed the bulk transportation of sherry in casks, and since then whisky distillers who want ‘sherry casks’ must commission and season them to order from coopers and bodegas in Jerez. The length of time sherry was in contact with the wood in a transport cask was between six and nine months; today, casks made specifically to mature Scotch whisky are first filled with mosto (fermenting grape juice) then with sherry (usually oloroso) for between one and four years before being shipped.

Around 95% of the casks filled by the Scotch whisky industry today are American oak. Most are seasoned with bourbon, not sherry.

To be described as ‘straight bourbon’ or ‘straight rye’, American distillers must fill their spirits into virgin (new) American white oak casks, according to a deal brokered by the American coopers’ union with the country’s distillers around 1936, and now embodied in the U.S. Code of Federal Regulations. If the barrels are refilled, the resulting whiskey may only be labelled ‘American whiskey’, which does not have the cachet of straight whiskeys.

The boom in demand for bourbon once Prohibition had been lifted in 1933, meant that by the late-1930s there were quantities of ex-bourbon barrels available to Scottish distillers. These began to appear in Scotland during the Spanish Civil War (1934-39) which curtailed the export of ex-sherry casks, and the trickle became a torrent after the conclusion of World War II. They were very much cheaper than ex-sherry casks; currently ex-bourbon casks are about one fifth of the price of ex-sherry casks.

Since the 1980s some brand owners have stated the cask-type simply as ‘sherry’ or ‘bourbon’. This is mis-leading in my view. Generally the first incumbent adds little to the flavour of the mature whisky: it is the wood type. Although the flavour of some whiskies from first-fill ex-bourbon casks may remind you of bourbon, this is owing to chemicals in the wood, not the spirit. The same is mainly true of ex-sherry casks, many of which are American oak, so it is more helpful to know the wood-type rather that the seasoning agent.