Sélection de Grains Nobles

Sélection de Grains Nobles (SGN) is French for "selection of noble berries" and refers to wines made from grapes affected by noble rot. SGN wines are sweet dessert wines with rich, concentrated flavours. Alsace wines were the first to be described as Sélection de Grains Nobles, with the legal definition introduced in 1984, but the term is also seen in some other wine regions France, such as Loire.

For Alsace wines, SGN is the highest official category for late harvest wines, while the step below is called Vendange tardive.

In 2001, the minimum must weight requirements for SGN in Alsace were increased to 18.2% for Gewürztraminer and Pinot gris, and 16.4% for Riesling and Muscat, expressed as potential alcohol. Only these four "noble varieties" may carry the SGN designation, or the Vendange tardive designation.

The required level ripeness of the grapes are as follows, expressed as sugar content of the must and potential alcohol:

These requirements make SGN roughly equivalent to a German Beerenauslese, but the Alsace style tend to favour slightly higher alcohol levels, which means that the residual sugar often is a little lower than in German wines, especially for Riesling and Muscat.

On rare occasions, the designation Quintessence de Grains Nobles (QGN) is seen for wines that significantly exceed the minimum requirements for SGN wines. Unlike the German designation Trockenbeerenauslese (TBA), QGN is no official designation, but it could be thought of as the Alsatian equivalent of a high-grade TBA. The term was invented in 1983 by Domaine Weinbach to describe an exceptional cuvee of that year's vintage, and while still used primarily by Weinbach, it has been adopted by a few other producers, including Marcel Deiss.

...
Wikipedia