Climate Classification
From MyWiki
Definition of cool
A warmer climate seems pretty easy to identify: lower acidity, higher alcohol, fuller body, sweeter, jammier fruit, overt alcohol, and high extract easily achieved. Too cold is pretty easy too: the grapes don’t ripen. This makes cool climate “just warm enough” to ripen fruit before the cold of autumn sets in.
Tasmania’s Dr Andrew Pirie, a cool climate specialist, postulates true cool climate as “regions with a mean January [or July] temperature equal to or less than 19°C or 1150 day degrees. It corresponds with the ability to ripen Pinot Noir, Pinot Gris, Traminer, Chardonnay and Sauvignon Blanc, but not Semillon, Merlot or Cabernet Franc, except in exceptional locations.” This would include Tasmania, Macedon, parts of Mornington and parts of the Yarra Valley.
Tasmania is undoubtedly Australia’s coolest climate, and it is reclaiming its main defining characteristic under the banner “true cool climate wines”. A look at Tassie’s key grape varieties – Chardonnay, Riesling, Gewürztraminer, Pinot Gris, Sauvignon Blanc, and Pinot Noir – pretty much confirm Pirie’s thesis. Sparkling wines are a forte.
Francine Austin, winemaker at Hardys’ Tasmanian Bay of Fires winery is very clear: “Cool climate is a combination of two things: finesse and elegance. A tightness of wine combined with power from a high concentration of aromatic flavour compounds.” For this, she says, “High sunshine hours and lower temperatures are needed, which retain delicate aromatic compounds. Acid degradation is slow, and ripening season day time temperature does not exceed 25°C.”
The science stuff
Drs. Amerine and Winkler (1944) defined five regions of California using a temperature index. Using a seven-month growing season, they calculated the “degree days” above 10°C (at which temperature vines generally start growing). Mean monthly temperature less 10 (degrees), multiplied by the number of days in the month, and totalled for the seven months. They came up with five regions, which still form the bedrock of viticultural climatic data. Their system has been variously refined, amended and critiqued, but not abandoned.
Region I is the coolest. Each region can be matched to the mean temperature of the warmest month (MJT) – January or July. From the regions that fit into the model, typical grape varieties can be identified. Dr. John Gladstones developed the model for Australia. Drs. Peter Dry and Richard Smart developed a homoclime approach, using a range of climatic measures including radiation, rainfall and relative humidity. Pirie brought in growing-season rainfall and humidity to the blooming algebraic calculation, to account for low vine-moisture stress during growing time.
Source: http://www.thedrinksbusiness.com/content/view/8377/333/
