Whisky on the Rocks
It sloweth age; it strengtheneth youthe; it helpeth digestion; it abandoneth melancholy; it relisheth the harte; it lighteneth the mynde; it quickeneth the spirite; it preserveth the head from whyrling - the eyes from dazelying - the tongue from lispying- the teethe from chatteryng - the throate from ratlyng - the guts from rumblyng - the hands from shiveryng . . . (Holinshead - 1578)
Yes, but what is this panacea, this nectar? If beer is the constant soul-mate of the geologist (M7, December 15,1989, p. 484) then this must surely be the preserve and just reward of the mining engineer or independent consultant.* It is of course, uisge beathe or whisky.
There are two types of whisky named according to the ingredients used in the manufacturing process. Grain whisky uses a mixture of malted and unmalted barley together with maize, whilst malt whisky is produced solely from malted barley usually derived from a single source. The water for each is unique and may be a burn, loch or spring.
Both types of whisky are mixed in different proportions in the production of blended whiskies, but many malts are also sold in their unblended state and it is with these unique single malts that this article is concerned.
It has been said that there are as many malt whiskies as there are stars in the firmament, but for our purposes we will be dealing in general terms with about one hundred and twenty.
With the exception of Bushmills from Northern Ireland, all U.K. single malt whiskies originate in Scotland and these are traditionally divided geographically into five groups. The groups are Highlands, Lowlands, Islands, Islay and Campbeltown. The most famous and concentrated area of malt manufacture is Speyside, a subdivision of the Highland classification, within which over forty-five distinct malts may be recognized.
In simple terms malt whisky is distilled beer. Indeed, several distilleries started in the last century as rather unsuccessful brewing operations and it was only with the introduction of distillation that a nondescript brew was transformed.
An important difference from the brewing process is that during the kilning of the barley, when the germinated growth is arrested by heating, peat is used as the main heat source and the peat-smoke is allowed to permeate the malt.
Two, and sometimes three, distillations of the wort take place in pot stills made of copper, the design of which has varied little since the early days of whisky making. The height of the still and the length of the condensing neck, together with the skill of the distiller, control the type and proportions of heavy aromatics that will be present in the condensate.
Even the specific geographical location of a distillery is thought to affect the nature of the distillate and it is clear that a combination of all of these factors is necessary to produce the unique and inimitable nature of each malt whisky.
However, it is generally accepted that the composition of the naturally occurring ground waters utilized in the production of the distillable liquor is also a major contributory factor. Unlike the brewing industry, no compromise is made by the chemical dosing of natural waters and each distillery utilizes its own source, the chemistry of which is dependent on the geological horizon from which it has arisen. Consequently, it is a fascinating exercise to look at malt whiskies from a geological rather than a geographical point of view.
Geologically, the oldest of the malt whiskies are the Precambrian Torridonian varieties from the shores of Lochin-daal on the west coast of Islay. Bowmore and Bruichladdich derive their water from streams crossing coarse red, green and grey grits and arkoses. These smooth, golden coloured, dry spirits compare markedly with the deep amber, full-bodied liquors distilled on the north-era and southern shores of the same island. Laphroaig, Lagavulin and Ardoeg, utilize . waters and thick, seaweed-containing peats developed on, and derived from, the phyllites of the Lower Dalradian. These peats and the characteristic bare and exposed coastal locations of the distilleries result in the unique smoky, iodine-like pungency.
To the south-east of Islay on the Mull of Kintyre the renowned Campbeltown malts use water derived from the mica-schists and slates of the Upper Dalradian. Regrettably, the sweet and smoky whiskies of Springbank and Glen Scotia are all that remain from over thirty distilleries.
Moving north-eastwards, but remaining within the Dalradian Supergroup, we find ourselves in the more variable succession of the. north-eastern. Gramr plans where waters may be derived from dioritic, psammitic and pelitic horizons which are interbedded with epidiorites, limestones and serpentinites. These rock types occur around the eastern tribu-. taries of the River Spey, along the banks of which are sited over twenty distilleries, the most notable ones of which include Tamnavulin, Glenfiddich and Convalmore. The water for Glenallachie flows over the granite of Ben Rinnes, the mountain which dominates the town of Aberlour. All the Dalradian whiskies in this area are pale straw to gold in colour and although individually distinct, are characterized by their sweet, fruity, spicy and light nature.
A much deeper colour, rich gold to deep amber, and a sweetness tinged by woody and nutty overtones characterize those whiskies derived from the intensely folded, grey Moinian metasedi-ments to the west. Particularly recommended examples of these fine spirits are Knockando and The Macallan.
The sole representative of water derived from Silurian strata is that used in the manufacture of Bladnoch, a pale amber coloured, light, dry and particularly distinctive whisky from Wigtown in Kirkcudbrightshire. The water originates in dark, graptolitic, Llandoverian shales.
Rocks of the Old Red Sandstone Group occur in two geologically distinct areas. To the south of the Highland Boundary Fault the red shales, marls, sandstones and volcanics of the Caledonian Cuvette extend from the coast west of Glasgow to the east coast around Brechin and Montrose. Water derived from these sources tends to be harder than that previously described and as a result gives rise to the dry, spicy flavour so characteristic of Glengoyne from the west, Glenturret from the centre and Lochside from the east.
The breccias, arkoses and sandy flagstones of the Orcadian Cuvette are a further important source of water for distilleries, though their wide distribution and the variability of the succession makes it difficult to define a characteristic trait of these Devonian malts. There is a complete range of flavours and colours varying from the deep amber of the sweet, rich and full Scapa from Orkney through to the light, golden Glenmoran-gie from Tain on the Dornoch Firth.
Water for the golden coloured, dry, spicy whiskies, Rosebank and Glenkin-chie, is derived from Carboniferous strata along the south side of the Firth of Forth.
The full-bodied flavour of the unique Jurassic whisky, Clynelish, may be sampled at Brora on the east coast of Sutherland where the well known non-marine sandstones of the Great Estuarine Series are developed.
Last, but by no means least in this foray into the geological world of malt whiskies are the two that draw their water from the volcanics of the Tertiary Igneous Province in the Western Isles. These are the little known but surprisingly pleasing soft, golden and sweet Tobermory from Mull and the well known and highly respected straw coloured, dry and peat flavoured Talisker from the desolate north-east coast of the Isle of Skye.
A true and full appreciation of malt whiskies can probably only just be achieved in a single lifetime. However, there can be no better way to educate oneself than to line a dozen or so of these fine distillates in stratigraphic order and work from oldest to youngest, remembering all the time the old Highland saying:
"one dram is alright, two is too much, three is too few".