GEOLOGY OF WINE 85
lavas of the Tertiary Volcanic Province provide surprisingly hard waters; these are seen in Talisker on Skye and Tobermory on Mull and across the water at Bushmills in the plains of Antrim in Northern Ireland. Rarely does a new distillery open, but the latest to do so was built in 1995 at Lochranza in the north of the Isle of Arran. The Isle of Arran single-malt whisky iswell into production and in one sense closes the circle with regards to a water source, in that it utilizes soft waters from the Easan Biorach, which flows over granite, having passed through thick peat beds. Waters used in whisky making, though more esoteric than brewing waters used for beer, are certainly less studied, and a full understanding of the effects
of water chemistry on whisky makinghas still to be achieved, but there can be no doubt that the effects are significant and demonstrable.
Engineering Geology: Ground Water Monitoring at Solid Waste Landfills. Geology of Beer. Geology of Wine.
Cribb S and Cribb J (1998) Whisky on the Rocks. Keyworth, Nottingham: British Geological Survey.
GEOLOGY OF WINE
J M Hancocky, Formerly Imperial CollegeLondon, London, UK
ß 2005, Elsevier Ltd. All Rights Reserved.
the supply of moisture and the rate at which the vine can take up nourishment through its roots; and variations in the composition of the ground, which will control the availability of nourishment supplied through the roots.
Geology can be important for the growers of grapes for wines; it can be ignored by theconsumer. Most of the arguments for the importance of ‘terroir’, which includes geology, have been along the lines: ‘‘This wine has one flavour, that wine has another flavour, yet they are made from the same grape variety’’. The difference must be something in the ground, i.e., it depends on the geology. Geologists have known for a long time that this is a misguided simplification. In the mid-nineteenthcentury, a distinguished French geologist, Henri Coquand, played a joke on the wine producers by stating that the quality of cognac (which is a distilled product anyway) was directly related to the quantity of chalk in the ground. The zones of quality for cognac are arranged in circles centred on Cognac: the strata have a roughly linear strike NW–SE. The best cognac comes from an area in whichchalk is largely absent. In spite of the obvious nonsense of a relationship between chalk and the quality of cognac, the idea is still being quoted today in some books. As with any agricultural product, there are many factors that control the quality of wine. Geology can play a part in three of these: the temperature around the vines in general and the bunches of grapes in particular; variations inporosity and permeability around the roots of the vine, which will affect both
It was known to Lucius Columella in the first century AD that the quality of grapes depends on the temperature around the vines. All modern work on the relationship between heat and grapes originates from Amerine and Winkler in California, who showed that each grape variety requires its own heat regimeto bring out the best of its qualities. Amerine and Winkler worked in California where, at that time, vines were kept around 1.1 m above nearly level ground. This meant that it was the general ambient temperature of the district which was the controlling factor. However, in many vineyard regions, the geology affects the mesoclimate, principally by its control of the topography. 1. Shelter fromcold winds. In more northerly vineyards (or more southerly vineyards in the southern hemisphere), the better vineyards are located on slopes which face south or south-west. Vineyards are not extended to the top of the hill, so that the summit can act as a break from cold winds from the north and north-east. It is even better if there is a clump of trees on the summit. This sheltering effect is of...
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