When many people think of Riesling, they picture drinking a chilled glass of unremarkable sweet stuff on a balmy summer evening. However, there are many quality Rieslings available in Milwaukee that are like golden rays of zippy sunshine in a bottle. And, these quality Rieslings are appropriate in both the doldrums of winter as well as in the throes of a heat wave. That's right, there is a Riesling suitable for every season and occasion -- from an informal picnic to the most elegant dinner.

Are All Rieslings Sweet?
The answer to this question is a resounding no, though some of the highest quality and most expensive Rieslings are indeed sweet.

If you are in a wine shop or supermarket and are unsure if the bottle of Riesling in front of you is sweet, look at the label for clues. The words dry, trocken (dry in German), halbtrocken (half-dry), classic and selection suggest the wine has a drier profile. If you don't see these words it's a safe bet the wine will have at least some sweetness to it.

Generally, though not always, a lower alcohol content (8-11 percent) could signal a sweeter Riesling. This makes sense because of how wine is made. In the production of wine, yeasts convert sugar in the grapes into alcohol in a process called fermentation. If the fermentation is halted either naturally or through the use of chemicals such as sulfur dioxide, the yeasts have not had a chance to convert all the sugars into alcohol. The result is a sweeter wine and a lower alcohol content. Likewise, if fermentation increases until little or no sugar remains, the result is a dry wine with a higher alcohol content.

On the other hand, grapes that are harvested very late contain a great deal of natural sugar and will not ferment completely, producing a rich, sweet dessert wine. Some examples are Late Harvest Riesling, Beerenauslese, Eiswein (Ice Wine) and Trockenbeerenauslese.

Geography
Most people think of Germany when they think of Riesling. While the grape variety has its origins in Germany and is also grown in Italy, Austria and France in Europe, its cultivation has branched out to far-flung places like Australia (including Tasmania), the United States and Canada. In the United States, major Riesling production has found a home primarily in the state of Washington, but other states like New York and Oregon, and even Wisconsin, Michigan and Virginia, make respectable and popular Riesling wines.

Something all these places have in common is a cooler climate. Interestingly, both the Riesling-growing regions of Germany and Washington lie between 45 and 50 degrees north latitude, and the southern hemisphere Riesling cultivation takes place roughly between 40 and 45 degrees south latitude.

The Riesling grape is naturally high in acid and requires a long, cool growing season in order to ripen fully. Slow ripening allows the grapes to maintain their fruity acidity as they develop ample sugars and absorb mineral characteristics from the soil. The resulting wine may vary in sweetness, but you can be sure that if it is well-made, the wine will have a nice balance between acid and sugar, an inimitable freshness and a unique flavor and bouquet, making for a tremendously satisfying drinking experience.

Because Rieslings are high in acid, many of higher quality are suitable for aging. As the wine ages, its flavors round out and subtleties not detected in the younger version may rise to the surface. A good example of this is goût de pétrole. It is literally a slightly oily, kerosene or petroleum smell and, to a lesser extent, tastes imparted to the wine from the unique soils on which the grapes are grown. For many, it is a highly desirable characteristic, and for others, not so much. In either case, it is truly distinctive.

Germany
Germany is the paramount producer of Riesling, currently the second most widely planted grape variety in Germany. Except for two regions, all of Germany's wine is produced in the southwest quarter of the country. Sun-reflecting water provides a warming effect, so most of the grapes are cultivated within two dozen miles of the Rhine River and its tributaries in regions called Mosel-Saar-Ruwer, Ahr, Pfalz, Rheingau, Nahe, Rheinhessen, Hessiche Bergstrasse, Mittlrhein, Franken and Baden. And, to impede cooling winds, most vineyards have been planted on slopes or steep hills topped by protective forests.

There are several classifications of German Riesling, depending on when and at what level of sweetness the grapes are harvested. At the lower end of the quality spectrum, just-ripe or even under-ripe grapes are used. These are made into wines called Tafelwein and Landwein, though you won't see them too often in the United States because they are mostly drunk in Germany by Germans.

The rest of the wines fall into the "quality wine" grouping (called Qualitätswein), which is further divided into a lower category QbA (Qualitätswein bestimmte Anbaugebeite) and higher one called QmP (Qualitätswein mit Prädikat). These are the wines to look for on our store shelves. Both are qualified based on where the Riesling grapes are grown, which specific varieties of grapes are used and grape ripeness at harvest. The QbA level allows the winemaker to take more liberties in manipulating the production process (for example, adding sugar to the juice before fermentation so that the resulting wine has more alcohol or is sweeter), and the QmP winemakers are much more restricted.