What to say about the Spey? Joseph Ward eases along the river and finds it's tops for single malts

Meandering through forests and farms and pretty stone-built villages, the Spey hardly looks like one of Europe's great rivers, but for Scotland's national drink, it is the equivalent of France's Rhone or Germany's mighty Rhine. There are distilleries throughout Scotland, with each region boasting a particular style, but nowhere are there as many—and, more important, as many outstanding—producers as in Speyside, the region along the banks of this Highlands waterway.

Most scotch is blended, a mix of malt whiskies made from barley and whiskies distilled from other, less expensive grains. A single malt is made only from barley, yeast, and water and is the product of one distillery. While not as significant commercially as widely marketed blends such as Johnnie Walker, J&B, and Cutty Sark, single malts are prized by connoisseurs. Glenfiddich, Macallan, Aberlour, Glenfarclas, and Glenlivet are among the great Speyside single malts.

The Scots have been producing whisky, sometimes legally but often not, for more than a thousand years. The modern industry dates to an 1823 reform of excise taxes that reduced crippling duties and ended widespread illegal production and smuggling. Still, taxes on whisky are higher in Britain than in many other EU countries, and Scots continue to view London warily.

The process hasn't changed much over the centuries, but technology has made consistency and quality control easier. Barley is soaked in water until it begins to germinate; then it is spread on the floor to continue the process. The germination turns starch into sugar. After a week to ten days, the barley is dried in kilns—traditionally over a peat fire, which gives the characteristic peaty, smoky aromas to some malts—and then ground up and mixed with hot water in large vats called mash tuns.

The resulting sweet liquid, called wort, is filtered, cooled, and then pumped into large wooden or stainless steel vats called washbacks. Yeast is added, and fermentation takes place over two or three days. (Up to this point, the process is similar to beer-making.) The fermented liquid, or wash, goes into a large pot-shaped wash still. The subsequent first boiling, or distillation, produces a liquid that is about 25 percent alcohol, called a low wine.

The low wine then goes into a smaller, though similarly shaped, alcohol still. Only the middle part of this second boiling, which has the fewest impurities, becomes whisky. The rest is mixed back into the low wines to be distilled again. The process is the same at every distillery. Dif-ferences in taste come from the type of barley, the amount of peat used in drying the barley, the water source, and the barrels in which the whisky is aged. (Recycled sherry and bourbon barrels are most common, but producers are increasingly adding port or Madeira barrels.)

Although blended scotch has long been the world's most popular whisky, single malts were not exported until the 1960s, when Glenfiddich, in the distinctive triangular bottle, began selling in England. 'The great single malts were at the heart of the finest blends,' says David Mair of William Grant & Sons, owners of Glenfiddich, 'and some distillers thought they were too particular a taste to find markets abroad. They are also more expensive to produce than blended whiskies.'