What's the Difference between Cool and Warm Climate Wines?

If you’ve ever been to a wine tasting or read tasting notes, you may have heard winemakers talk about cool or warm climate wines.  Though you might not have known what it meant, understanding how the climate impacts winemaking and flavour can help you make better wine choices. 

by Erin Ogilvie  

How does climate affect the flavour of wines? 

First of all, let’s clear up one misconception about cool climate wines: that the region has to be ‘cool’ all year round.  The regions are actually categorised based on how quickly the cooler weather comes on, how much rainfall they receive, and the typical humidity, as well as their lower average temperatures.

The Yarra Valley in Victoria is a cool climate region.  While maximum temperatures average 27C in the summer, the average minimum drops below 10C by March and stays that way until January.  On the other hand, in NSW’s Hunter Valley, a warm region, the average maximum temperature is around 30C over summer, and the average minimum only drops below 10C between May and September.

 

Resources: Hunter Valley | Yarra Valley 

Cool Climate Wines

Cool climate grapes do not ripen as quickly, resulting in lower natural sugar and therefore higher natural acidity.  The wines are often described as being more subtle or refined.  You’ll find more tart flavours (such as raspberry, cherry, or cranberry), as well as green or spice characteristics (you might hear a winemaker describe the wine as smelling like “the forest floor”).  

There are a number of challenges that cool climate winemakers face.  Cool climate vines tend to yield less fruit, and some varieties will struggle to thrive without warmer temperatures.  The winemakers also need to ensure the wine’s savoury characteristics are balanced with enough fruit and sweetness to create a wine that is not stringent and sour.

Cool Regions: Yarra Valley, Geelong, Macedon Ranges (VIC), Adelaide Hills, Eden Valley (SA), Tamar Valley (TAS)

Ideal Varieties: Riesling, Chardonnay, and Pinot Noir, which is why Australia’s best sparkling wines tend to hail from these regions, like Ed Carr’s Arras (made from Chardonnay and Pinot Noir grapes grown across Tasmania). 

 

Warm Climate Wines

Warm climate wines tend to pack more of a punch, often described as full-flavoured or rich.  The grapes in this region ripen quicker so have higher natural sugars, and therefore often have higher alcohol levels. Typically, you’ll see dominant fruit flavours (think stone or dried fruit, or dark fruit such as blackberry or plum), as well as more ‘muscular’ characteristics (such as black pepper, leather, or chocolate).

The winemaker’s biggest challenge is controlling the wine’s big fruity flavours and high alcohol content, which can be achieved by adding acidity.  The grapes also tend to have thicker skins to protect themselves from the heat, which results in more tannic wines.  These dominating factors need to be balanced during the winemaking process, or it risks becoming overwhelming and nondescript.

Warm Regions: Hunter Valley, Mudgee (NSW), Clare Valley, Barossa Valley, McLaren Vale, Coonawarra (SA), Margaret River (WA)

Ideal Varieties: Shiraz and Cabernet Sauvignon, which is why the “blend that defines Australia”, Shiraz Cabernet (or Cabernet Shiraz), is usually produced from grapes grown in warm regions.

 

Stephen Henschke talks to us about growing and producing wines from both cool and warm climates: 

"Climate is a major contributor to flavour.  Our wines are produced from organically and bio-dynamically farmed sustainable vineyards in South Australia’s Eden Valley, Barossa Valley, and the Adelaide Hills.  In our case, the high altitude of the Mount Lofty Ranges plays a significant role on the wine.  It results in delayed ripening, so the fruit is picked later during autumn when it is cooler.  For example, the same varieties ripen two weeks later at Lenswood in the Adelaide Hills than at Eden Valley.  Longer slower ripening results in increased flavour intensity, tannin structure, and balance in the wine.

"The higher altitude of the Eden Valley results in more distinctive varietal flavour characteristics and higher acidities.  Eden Valley produces stunning signature Riesling and elegant Shiraz, that show extraordinary flavour, purity of fruit and the potential for excellent ageing. Hill of Grace and Mount Edelstone are both single vineyard Shiraz wines produced in Eden Valley.  The Barossa Valley produces full flavour Shiraz and Cabernet Sauvignon, and the cool climate Adelaide Hills provides higher rainfall and humidity at the right time of the year, cooler temperatures to retain natural acidity, and still enough sunshine to fully ripen the grapes.

"For example, we describe our Julius Eden Valley Riesling as having florals, lime zest, and stone and citrus fruit flavour intensity, good acidity, and extraordinary palate length.  However, our Lenswood Green’s Hill Riesling has delicate floral fragrance, citrus blossom and slate, citrus fruits and a mineral texture, plus higher acidity and a pure fine finish.  The Adelaide Hills Rieslings often age in the bottle longer than the Eden Valley Rieslings.”