Expression of Regionality 

Rieslings are made in the vineyard and are an expression of their place. Winemakers become
the custodian of the grapes in the winery.

Good Riesling is like a window into the vineyard, reflecting very clearly where and how it is grown. Many experts agree that Riesling best expresses the notion of terroir, which considers the complete influence of the natural environment (soil structure, topography, sunlight, water) on the vine, as well as the human interaction with this particular environment.

Though it may sound strange, Riesling has a transparency about it - a heightened sensitivity to its surroundings. Riesling responds best to cool climates and nutritionally poor soils with high mineral content. When you manipulate Riesling away from its natural environment, it will create mediocre wines that lack complex character and vitality.

From Riesling Rules, Pacific Rim