What is Riesling?
Quick answer
Riesling is a noble white grape from Germany's Rhine Valley, considered by many experts to be the world's greatest white grape. It produces wines of exceptional aromatic purity (lime, petrol, flowers), vibrant acidity and remarkable ageing potential, from bone-dry to lusciously sweet.
Detailed answer
Riesling is the aristocrat of white grapes. First documented in Germany in 1435, it has achieved a stylistic perfection few varieties can match.
Its defining trait is the ability to retain high acidity even at full ripeness, allowing it to produce wines ranging from bone-dry to lusciously sweet — all underpinned by an acid backbone that provides freshness and longevity. A great dry Riesling can age 20 years; a sweet Riesling, 50 years or more.
In Germany, Riesling covers about 24,000 hectares and dominates the finest sites in the Mosel (slate soils), Rheingau and Pfalz. The German classification system runs from Kabinett (lightest) to Trockenbeerenauslese (TBA, concentrated by noble rot). Dry ("Trocken") Rieslings are gaining popularity.
In Alsace, Riesling is the noblest of the four Grand Cru varieties. Alsatian versions are typically drier and more powerful than German ones, with lemon, petrol and pronounced minerality. Vendanges Tardives and Sélections de Grains Nobles are treasures of concentrated sweetness.
Australia (Clare Valley, Eden Valley) makes crystalline dry Rieslings. Austria (Wachau), New Zealand and Canada (Niagara, for ice wines) also offer excellent expressions.
The signature "petrol" (or kerosene) note in aged Riesling comes from TDN (1,1,6-trimethyl-1,2-dihydronaphthalene), a chemical compound that develops with age. It is considered a mark of quality and typicity.