While it might seem like a party trick, blind tasting helps those who sell and study wine to better understand styles, regions and typicity.
But certain varieties often confuse tasters. Called “wine twins,” these duos might share chemical makeups, agricultural and winemaking practices, or characteristic styles.
What are the trickiest wine twins, and how do pros tell them apart?
“Aromatic white varieties often present challenges because there are six key terpenes [in most of them],” says Deborah Parker Wong, global wine editor for SOMM Journal.
Linalool, terpineol, citronellol, nerol, geraniol and o-treinol are all present to create the signature floral and citrus notes in aromatic varieties like Alvarinho.
Alvarinho, specifically bottlings from the Monção-Melgaço region in northern Portugal, is richer and fuller bodied than the more commonly understood floral expressions of Albariño from Rías Baixas.
“The terroir is far warmer, drier,” says Parker Wong. “So, the Alvarinho here is more like an Alsatian Pinot Gris—another warmer, drier region which benefits from the rain shadow of the Vosges, in intensity and body than, say, a Pinot Grigio from the Veneto.”
The wines’ weight, fuller mouthfeel and, in some cases, similar terpene elements can make them seem alike to tasters.
However, if you place them side-by-side, Alvarinho shows more overt floral aromas and stone fruits, Parker Wong says. Pinot Gris is more restrained, and expressions from grand cru vineyards in Alsace often boast upfront mineral notes alongside more subtle stone fruit characters.
“Both Sangiovese and Nebbiolo are relatively thin-skinned grapes, which, all things being equal, creates wines with lighter color and lower, bitter/drying tannins,” says David Glancy, MS, CWE, founder and CEO of the San Francisco Wine School.
Both have a medium-red hue in the glass, often with an orange-tinted rim. On the palate, they present red fruit aromas and medium-to-high tart, mouthwatering acidity.
Winemaking practices also play a role in the grapes’ similarities.
“In their respective homes of Toscana and Piemonte, they are typically given a fairly long maceration,” says Glancy. “The most common practice is aging in botti, large, used oak vats, allowing oxygen exchange without imparting strong vanilla or spice notes from new, small oak barrels. So, both the structure of the grapes and the winemaking make the wines quite similar.”
When it comes to differentiating them, Glancy finds that Nebbiolo typically displays a more noticeable orange rim, higher tannins and higher alcohol. These differences can be quite nuanced, though. He recommends side-by-side tastings.
Other wine twins express themselves similarly on the vine and in the glass.
“While many wines are easily confused for one another, especially as climate change has an increasingly larger impact, I’ve found that Argentine Malbec and California Zinfandel are frequently confused,” says Christopher Tanghe, MS, interim executive director of GuildSomm.
Both have juicy, dark red and black fruit notes, elevated acidity and what Tanghe calls “dusty minerality.”
Some of these commonalities are due to winemaking practices.
“The trend for oak treatment on both varieties has shifted, with much less used these days,” says Tanghe. “So, the fruit really pops in a pure expression, showing the crossover between the two in how they each walk the line between red and black fruits.”
The key to distinguishing between the two is tannins.
“Malbec has more powdery tannins, similar to the texture of cocoa powder,” says Tanghe. “Zinfandel’s are less powerful and silkier.”
Zinfandel has another wine twin, says Tim Gaiser, MS, a wine educator, speaker, writer and researcher. He says that Syrah and Zinfandel often confuse his students. Uneven ripening leads to raisinated and green fruit characteristics. The wines also have similar spice and herbal qualities like black pepper, fresh and dried herbs, mint or eucalyptus.
The wines can also be quite similar in structure.
“Syrah, especially New World wines such as Barossa Shiraz, and Zinfandel can both show an elevated level of alcohol, often above 15%,” says Gaiser. “And both grapes tend to be in the same tannin range, between medium and medium-plus.”
Gaiser advises focusing on non-fruit elements.
“Regardless of origin, Syrah/Shiraz usually displays smoky, gamy, dried meat and leather notes not found in Zinfandel,” he says. “Northern Rhône Syrah can be more extreme, displaying iodine, dried blood and iron notes, and have considerable earth and mineral qualities.”
Fruit aromas and flavors are rarely helpful in blind tastings, Gaiser says. “Focus on fruit character and quality,” he says. “Is the fruit tart, candied, raisinated?”
And, of course, practice makes perfect. So taste, taste, taste.