Riesling

Riesling: Purity, Acidity, and Age-Worthiness

Riesling is defined above all by one characteristic: it retains very high natural acidity even as it fully ripens. This acidity is what allows Riesling to make everything from bone-dry, mineral wines to the world's most luscious sweet wines while always tasting balanced and fresh.

Grape Characteristics

• Acidity: very high and persistent, the defining feature of the variety
• Aromas: floral (blossom), citrus (lime), and orchard fruit (green apple, and riper apricot at higher ripeness levels); with bottle age, Riesling famously develops a petrol/kerosene aroma, generally regarded as a positive sign of maturity rather than a fault
• Vineyard behaviour: buds and ripens late, requiring a long, cool growing season to develop flavour while preserving acidity — this makes it best suited to cool climates
• Winemaking: almost always made with minimal intervention — fermented in stainless steel, rarely oaked, letting the grape's own purity and site character show through
• Sweetness range: capable of the full spectrum from bone-dry to intensely sweet, including botrytis-affected and frozen-grape (icewine) styles

This hands-off winemaking approach means that, more than almost any other principal grape, Riesling's finished style is a direct reflection of where it was grown and how ripe the grapes were at harvest, rather than of cellar technique. This is one reason Riesling is often considered one of the most "transparent" or terroir-expressive white grapes in the world, and why WSET places such emphasis on the vineyard and climate factors covered earlier in this guide when studying it.

Germany: The Prädikat Ladder

Germany is Riesling's spiritual home, with three key regions showing distinct styles:

• Mosel — steep slate slopes, light body, very high acid, lower alcohol; off-dry styles are common, with intense green-fruit and mineral character
• Rheingau — fuller-bodied than Mosel, with more dry (Trocken) styles and riper orchard-fruit character
• Pfalz — warmer, riper stone-fruit character, fuller body, and more dry examples

German quality wine (Prädikatswein) is classified by the ripeness of the grapes at harvest (measured by must weight), not necessarily by the sweetness of the finished wine:

The terms Trocken (dry) and Halbtrocken (off-dry/half-dry) can be applied across several Prädikat levels to indicate the finished wine's actual sweetness, since ripeness at harvest and final sweetness are not the same thing.

Alsace

Unlike Germany, Alsace has a tradition of fermenting Riesling fully to dryness, producing full-bodied, high-alcohol, intensely aromatic wines with excellent ageing potential and strong food-pairing versatility. Alsace Grand Cru vineyard sites represent the region's highest quality tier.

Australia: Clare Valley and Eden Valley

Clare Valley and Eden Valley, both in South Australia, achieve a cool growing climate through altitude despite being in an otherwise warm country. The resulting Riesling style is famously bone-dry, with intense lime character, high acid, and pronounced minerality — typically bottled under screwcap and capable of developing the classic petrol note with several years of age. This Australian dry style is often cited alongside Alsace as proof that Riesling does not need residual sugar to show its full aromatic complexity.

Why Riesling Ages So Well

Riesling's combination of very high acidity and, in many styles, residual sugar makes it one of the most age-worthy of all the principal white grapes — both acid and sugar act as natural preservatives, allowing well-made Riesling to develop for a decade or more in bottle. As Riesling ages, its primary floral and citrus aromas gradually give way to deeper, more complex notes: honey, dried fruit, and the distinctive petrol/kerosene aroma (caused by a compound called TDN that develops naturally in the bottle, especially in wines exposed to warmth or sunlight during ripening). Far from being considered a fault, this petrol character is prized by Riesling enthusiasts as a hallmark of a mature, well-developed example, and it appears across dry and sweet styles alike, from Australian Clare Valley to German Spätlese.

Riesling and Food

Riesling's acidity and aromatic intensity make it exceptionally food-friendly. Off-dry German styles are a classic match for spicy Asian cuisine, where a touch of sweetness tempers chilli heat while high acidity cuts through rich or fatty elements. Bone-dry Alsace or Australian Riesling pairs well with delicate seafood, poultry, and salads, while the intensely sweet Beerenauslese and Trockenbeerenauslese styles are traditionally served with fruit-based desserts or enjoyed on their own, their sweetness balanced by equally high acidity so the wine never feels cloying.

Key Takeaway for the Exam

Remember that Riesling's high acidity is what allows it to succeed across the full sweetness spectrum, that German Prädikat levels describe harvest ripeness rather than guaranteed finished sweetness, and that Alsace and Australia represent classic dry expressions in contrast to Germany's traditional range. The combination of high acid, aromatic purity, and (in many styles) residual sugar is also what gives Riesling its outstanding ability to age gracefully in bottle.