What factor contributes to the full-bodied nature of Australian Shiraz compared to Syrah from the Northern Rhône?

The full-bodied nature of Australian Shiraz in comparison to Syrah from the Northern Rhône primarily stems from the warmer climate in which the grapes are grown. In Australia, the generally warmer climate allows for a longer growing season, leading to riper grapes with higher levels of sugar. This results in wines that are often more concentrated, rich in flavors, and higher in alcohol content, contributing to the full-bodied characteristic that is typically associated with Australian Shiraz.

Warmer conditions also encourage the development of fruity flavors and aromas, which enhance the overall mouthfeel and body of the wine. This is in contrast to the typically cooler climate of the Northern Rhône, where Syrah tends to have a lighter body with more acidity and a different flavor profile, often exhibiting more savory and earthy notes.

Factors such as grape clones, sugar levels, and aging processes can influence wine characteristics, but the primary difference in body between these two styles is rooted in the effect of climate on grape ripeness and concentration.