Fine weather makes fine wine

After varietal selection and site location, the most important factor for a vineyard is the yearly impact of weather on the harvest. Temperature, rainfall, humidity, wind and sunlight combine to determine the quality of any given vintage.

If the temperature drops below minus 15 for a prolonged period in winter, dormant vines will die. This is why the County is not alone in the practice of burying vines. The fertile grape-growing crescent bordering the Black Sea at the mouth of the Don River is subject to winter kill and, in many cases, the vines have to be hilled up as we do here. The winter cold, ironically, is needed to kill off pests and diseases. But an early autumn cold snap can prevent the fruit from ripening fully.

Rain really has to fall at the “Goldilocks” time, and in just the correct amount. Too much rainfall in the latter part of summer encourages mildew. Heavy rains prior to harvest will dilute the sugars, acids and flavours. Too much water requires careful drainage planning in the location of the vineyard and the planting of the vines. Too little water is almost preferable: established vines are forced to drive their roots deep into the ground in search of the water table. And grape-growers with access to irrigation (as Mendoza) can always make up any shortfall through water allocation.

Summer winds can have a positive effect by cooling the vines and drying out wet vineyards. Warm mistral winds from North Africa, however, can close down the vines in the Rhône valley. Winegrowers there erect windbreaks to disperse this wind. Californian costal vineyards create similar barriers, but for the opposite reason: the cold prevailing sea winds off the Pacific can sometimes delay the ripening process. Strong spring winds anywhere might delay or damage flowering.

Finally, sunlight is critical, both for the process of photosynthesis and the heat — without which the fruit could not ripen.

Every year is a new adventure in temperature, rainfall, wind and sunlight. That is why every vintage is unique.

THIS WEEK’S PICK
This week I was introduced to Devils Wishbone 2012 Cabernet Franc ($25) made by owner/winemaker Paul Gallagher. Located south of the Lake on the Mountain, his vineyard and winery can boast of a 15-acre terroir ideal for grape growing.

This wine, made with estate fruit, shows a bouquet of mace, vanilla, licorice all-sorts, and wild east coast red currant preserve. The palate is firm with ripe cherry, red currant and black raspberry. A smooth lingering finish, created by the deft aging in French oak, makes this a wine to savour.