In the world of wine, Riesling stands out for its incredible versatility, making it an excellent choice for crafting a wide range of white wines. From crisp, refreshing dry whites to lively sparkling wines, and from lusciously sweet dessert wines to distinctive late-harvest, botrytized, and ice wines—Riesling is everywhere, showcasing its “jack-of-all-trades” nature.
Yet, no matter the style, Riesling wines often carry a unique “petrol-like” aroma. This distinctive note seems out of place in the typical wine flavor spectrum, yet it has become one of Riesling’s most iconic traits. Some enthusiasts hail it as a mark of premium Riesling, a sign of exceptional quality, while others view it as a flaw, believing it disrupts the wine’s purity and harmony.
So, where does this seemingly incongruous petrol note come from?
Why Does Riesling Wine Have a Petrol Aroma?
Scientists attribute Riesling’s petrol aroma to an aromatic compound called TDN (trimethyl-dihydronaphthalene). This compound isn’t naturally present in the grapes but develops gradually during the wine’s aging process.
Over time, the wine’s increasing acidity triggers the hydrolysis of carotenoids (naturally occurring pigments in grapes), ultimately forming TDN. Riesling grapes, with their naturally high acidity, accelerate this hydrolysis, making them more prone to developing petrol notes as they age.
It’s worth noting that TDN levels aren’t fixed—they’re influenced by factors like climate, soil type, and grape ripeness, which is why Rieslings from different regions exhibit varying intensities of petrol character.
Is a Petrol Note a Flaw or a Feature?
For winemakers who prioritize perfect balance, the petrol note is often seen as a flaw. Legendary Rhône winemaker Michel Chapoutier has openly stated that Riesling’s petrol aroma is a direct result of over-pressing or oxidation. In his view, it masks the wine’s natural floral and mineral qualities, disrupting its harmony—a clear sign of poor winemaking.
However, some winemakers embrace the petrol note. Adam Eggins, chief winemaker at Australia’s Wakefield/Taylors Wines, is one such advocate. He considers it a hallmark of high-quality Riesling, particularly in wines made from low-yield, late-harvest, high-acidity grapes, where the petrol note is more pronounced and a mark of excellence.
Ultimately, whether Riesling’s petrol note is a flaw or a feature has no definitive answer—it comes down to personal preference. Some wine lovers appreciate the added complexity and depth it brings, while others prefer cleaner, fresher flavors and steer clear of it altogether.
Riesling’s Classic Regions: A Global Flavor Journey
Exploring Riesling’s characteristics not only demystifies its petrol aroma but also takes us on a global tour of its classic regions, each offering unique expressions of the grape:
Germany – Mosel
The Mosel region, with its cool climate (average July temps of just 18°C), plants its vineyards on steep slate slopes to maximize sun exposure. The poor soil forces vines to dig deep for water, while the heat-retaining slate ensures slow ripening, leading to high acidity and TDN potential.
Flavor profile: Light, high-acid, low alcohol
Typical aromas: Green apple, white peach, slate minerality
TDN level: Moderate to pronounced
France – Alsace
Alsace produces fuller-bodied, higher-alcohol Rieslings. With less rainfall, the grapes achieve higher ripeness, resulting in more pronounced TDN and flinty mineral notes.
Flavor profile: Rich, dry, high alcohol
Typical aromas: Citrus, honey, flint
TDN level: Noticeable
Australia – Clare Valley
Clare Valley’s dramatic diurnal temperature shifts and limestone soils give its Rieslings vibrant acidity and minerality. Young wines showcase lemon and green apple, evolving into honey, toast, and petrol with age.
Flavor profile: Zesty acidity, strong minerality
Typical aromas: Lemon, petrol, toast (with age)
TDN level: Pronounced in aged wines
Riesling’s petrol note is both a product of chemistry and a testament to terroir and time. It may not be universally loved, but there’s no denying that this unique complexity makes Riesling one of the most distinctive varieties in the wine world.
Next time you open an aged Riesling, take a moment to savor that subtle petrol whisper—it’s not just a scientific marvel but a story of sunlight, soil, and craftsmanship.
