The most famous German Riesling vineyards lie along the Rhine river, where solar rays are reflected up the slate-covered hills and onto vineyards. The slate in the soil also help by storing heat, raising the temperature in an otherwise very cool area, thereby making for terrific growing conditions.
In the New World, Riesling suffered from attempts to make German-style sweet wines. Some years ago, a focus on dry yet refreshing production with floral aromatics led to a renaissance. Unfortunately for this grape and its producers, the old image of over-produced and dull has made it a rather unpopular variety amongst the general public. Therefore, until a consumer renaissance elicitis the advent of Riesling again, it will be prevalent only within the wine industry.
Alsace (France), Germany (Rhine and Mosel), Canada, New Zealand, and Australia (Clare Valley).
In the New World, Riesling is commonly made dry with marvellous perfumed wines, some with blossom, citrus, apricot, lavender, lemon, peach and linden flower aromas. The palate is often clean with a fresh acidity. With age, aromas of kerosene, honey, clove and even toast develop over a more full and weighty palate.
Sweetness is common in Germany, but the labelling is sometimes complicated. While the legal labelling system is narrow, the following terms are deployed on labels.
Trocken (dry) can be added to any label to mark that the wine has been made into a dry style by fermenting all grape sugar into alcohol, which however elicits a very strongly alcoholic wine.
Kabinett (early harvest) is often of low sweetness.
Spaetlese (late harvest) often has a medium level of residual sugar.
With Auslese (select harvest), the fruit is usually riper than Spaetlese and so a sweeter wine results.
Beerenauslese (selected harvest of berries) enjoys a higher prestige than Auslese, and is picked later. The grape bunches are affected by a Botrytis fungus which removes water and increases natural sugar. The berries must be hand picked and make sweet, concentrated wine for long ageing.
The highest level and intensely sweet wines result from Trockenbeerenauslesen. The berries have been shrivelled by Botrytis and may look like raisins. The very high sugar and very low juice from the berry makes very little wine and so the wine is very expensive and rare. It is considered a dessert wine.
Eiswein (ice-wine) is also made using Riesling. The process requires a natural freezing of the grapes while still on the vine; the frozen water in the juice makes for a richly concentrated wine. As bunches are typically ready for picking in late summer, waiting for freezing weather can cause problems and loss of vintage. It is important that no Botrytis affects the grapes for clean Eiswein to be made.
Sugar added to grape must (crushed grape juice and skin) to increase sweetness or alcohol level makes Qualitatswein. This is not a technical level to identify sweetness, but rather an identification of adherence to a classification of wine making, and is a term commonly applied to wine from Piesporter.
All Riesling is vinified without oak.