The Fundamentals of Wine Character
There are four fundamental factors that give wine with its characteristics: grape variety, soil, weather and winemaking technique.
1. The Soil
The rich, low-lying valley floors and river deltas where so many crops thrive are not usually the best locations for growing wine grapes. The grapevine seems to prefer gravel to earth, and grows well in rocky hillsides where no other crops will. It does its best when forced to dig deep for its water, sometimes as much as 3m down.
The French wine producers believe strongly in the importance of the geographical region of origin. Soil, they believe, is an essential part of terroir, and helps to give wine its distinctive character. Each of the major wine regions of France has unique soil characteristics. For example, the Graves subregion of Bordeaux gets its name from the gravelly soil deposited along the Garonne River by the most recent glacial advance. The red wines of the Graves are among the most powerfully flavoured reds of Bordeaux, and the acidic, crisp whites are among the finest white wines in the world.
'Terroir' a key word in the wine world cannot be translated directly into English. Generally speaking, terroir means the total natural environment a grape is grown in, which comes down to three key factors: the soil, the macroclimate and the microclimate.
2. Grape Variety
There are many types of grapes within the species Vitis vinifera, all with their unique identifying characteristics. The term 'varietally correct' is used to describe wines whose qualities are consistent with their predominant grape variety. For example:
Cabernet Sauvignon
- Colour: deep purple or red
- Flavour: moderate acidity balanced by fruit flavours, firm tannin, long progression of flavours on the palate.
- Aroma: blackcurrants, chocolate, green pepper, mint; jammy fruit when young, cedar and tobacco with age.
Sauvignon Blanc
- Colour: pale gold, sometimes greenish.
- Flavour: crisp, prominent acidity, herbaceous and fruity flavours.
- Aroma: in cooler climates cut grass, nettles, gooseberries and asparagus; in warmer climates wines will often display tropical fruit, particularly passion fruit.
However, this is not to say that all Sauvignon Blancs or Cabernet Sauvignons smell or taste the same. The fact that there are so many different styles available indicates the importance of the other three factors. Grape varieties have inherent characteristics that can be altered or reinterpreted by the soil, the weather and the winemaker's technique.
3. Weather
Soil is the most constant factor in wine-making; the mineral composition of a vineyard barely changes in a hundred years. The weather in a given growing season, though somewhat predictable (based on historical trends), is the reason that we have good years and bad years for wine.
Spring
For the best wine, early springtime should remain cool. An early heat wave may cause leaf buds to develop prematurely, only to be killed by a cold night's frost. Spring is one of the only times that plentiful rain is welcome; it becomes desirable as the growing season progresses.
In the Northern hemisphere, grape leaves unfurl in late April, followed by flower buds in late May. The vineyards of the Southern Hemisphere (Australia, South Africa, New Zealand and South America) will flower six months earlier. Hail is particularly dreaded during this critical flowering month, and high winds and heavy rain will also interfere with pollination during this time.
Summer
After the vines have been pollinated, the grapes need about three months to ripen completely. An occasional gentle rain is welcome in early summer, as it helps to fill the grapes with liquid to plump them up to the proper size. A drought year would result in small grapes with a high skin-to-pulp ratio. Having more grape skin will produce a more tannic, intensely flavoured wine.
As the grapes mature, a dry and cool breeze will help to keep the grapes free of disease and to slow the ripening process. Grapes that ripen too quickly tend to develop less flavour.
Autumn
September is a crucial month. A dry and warm September can rescue a terrible vintage, and a cold and rainy September can ruin a previously perfect growing season.
As the grapes do not all ripen at the same time, the grape pickers spend September making pass after pass through the rows of vines, picking only the grapes at the exact point of ripeness. An imminent rainstorm leaves a vineyard manager with a difficult choice - either to pick the grapes a few days shy of perfect ripeness, or alternatively to pick rain-swollen grapes after the storm and run the risk of rot.
Cool weather is desirable during the fermenting period. The cool breezes around the tanks help to prolong the fermenting process and prevent overheating.
In Germany and Canada, a well-timed winter freeze makes eiswein (ice wine) possible. The grapes are harvested after being frozen in the vineyard and then, whilst still frozen, they are pressed. The water is driven out as shards of ice, leaving a highly concentrated juice, very high in acids, sugars and aromatics.
4. Winemaking Technique
Each and every vintage will yield grapes of unique character, and it is the task of the winemaker to make the best use of each harvest. The weather may cause a number of problems, which the winemaker must use their skill and experience to overcome, as shown in the table below.
| Problem | Cause | Solution |
|---|---|---|
| The first vine buds destroyed. | A frost following an early warm spell. | Sprinkle the vines with mist to cover them with a protective shield of ice, which will insulates them from colder, more harmful temperatures. |
| Inadequate ripening of the grapes. | A cold, damp summer. | Add calcium carbonate to soften the acidity associated with under-ripeness. |
| Under-ripe red grapes which lack the concentration of desirable components in the skin-pigment, tannin and fruit flavour. | A cold, damp summer. | Allow the skins to macerate in the juice for a longer time than is usual. |
| Inadequate ripening of the grapes, leading to insufficient sugar to ferment to the desired alcoholic strength. | A cold, damp summer. | Add sugar prior to fermentation (chaptalization). |
| Grape rot. | Frequent rainfall later in the season. | Can be combated with a sensible use of chemicals. |
The winemaker will have to make many other choices, always balancing quality with cost. Stainless steel or oak? New oak or old oak? How much press wine should be blended back into a wine made from free-run juice?
Ideally, in making these and other choices, the winemaker brings out the best in the grapes, and from them crafts a wine that reflects the hereditary qualities of the grape variety and the unique composition of the soil, and addresses any problems caused by the weather.
