VINE AND VARIETY

The grape
The grape variety is of vital Importance in shaping wine styles. At its most basic, it determines the color of the wine: you cannot get red wine from white grapes (although you can get white wine from red grapes). After that, choice of grape influences the levels of acidity, alcohol and (in red wines) tannin, as well as the body and style of the wine. The variety also determines how the winemaker will approach the wine. Few winemakers would age riesling in oak or put it through malolactic fermentation. Conversely, no winemaker is going to prevent the malolactic fermentation in cabernet sauvignon, and most will give it some oak treatment.

The typical wine grape is quite small. Even with white wines, some flavor comes from the skin, and a low juice-to-skin ratio enhances those characters. In black grapes (also known as red grapes), the skin gives the wine its tannin and color. Thicker skins and/or smaller grapes mean deeper color and more tannic wine.

The variety, of course, also gives the wine its core flavors. Each variety may have a range of typical aromas and tastes-its "flavor spectrum." No wine will display all of these flavors, but a reasonably good wine should show at least one or two flavors to give good varietal character, and a complex wine will display more.

The flavor spectrum for shiraz, for instance, includes herbs, mint, spice, pepper, raspberry, cherry, mulberry, blackberry, plum, cassis, black olives, aniseed, liquorice, prune, stewed plum, chocolate, jammy and raisin. The primary fruit in shiraz develops, in that order moving generally from fruit grown in a cool climate (or which may be under ripe) to fruit from warm areas (which may be too ripe).

Though there may be some overlap between varieties, the flavor spectrum differs from variety to variety. Thus, shiraz may show a white pepper character, but cabernet sauvignon should not. Both types of wine, however, may display plummy or curranty flavors.

The condition of the fruit is also important. In cool regions, under ripe fruit will give harsh green characters to the wine and, if it is damp, disease could dull or spoil the wine. In hot climates, the grapes may become overripe, giving hot alcohol and jammy flavors that lack balance and complexity.

While the variety shapes the style of wine, the climate modifies how each variety develops. Riesling grows well in a very cool climate because it can become flavor-ripe while it is barely physiologically ripe. Thus, intense rieslings are made in northern Germany with a potential alcohol content of about 9 percent-relatively speaking, a small amount on a world scale-and showing a comparatively low level of sugar content at ripeness. But the same variety also flourishes in the Clare valley-a warm, if not baking hot, region of South Australia-where it makes fuller but still intense styles of wines.