Riesling can be quite distinctive. And, generally, but not always, fairly straightforward to spot in a blind tasting (can sometimes be confused with Pinot Gris/Grigio and vice versa). If blind tasting in an exam situation, spotting it can be one thing but getting full marks for doing so can be quite another.
In the white paper of the 2014 MW exam, for example, there was a flight of four Rieslings. Phil Tuck MW commented in the feedback that virtually all candidates correctly identified them as Riesling. However, nobody got full marks. Phil went onto stress the importance of having the key facets of all the different styles of Riesling from around the World at one’s finger tips. The list below is by no means representative of this. But it gives some strong general pointers for Riesling that may help justifying its identification in a blind tasting.
- Racy, crisp and focused acid
naturally high in acidity (a moderate to late ripening variety). Typically grown in cooler climates (or harvested early) this acidity is accentuated
- Expressive and intensely aromatic
high level of terpenes is a defining feature of Riesling (although Muscat and Gewurztraminer are much higher). Aroma intensity is highly correlated with terpene concentration in wine
- Citrus (particularly lime and lemon) and floral notes dominant
the major terpenes in Riesling include: Citronellol (citronella), Hotrienol (lime), Geraniol (grapefruit), Nerol (mandarin), Linalool (rose aroma), and Alpha-terpineol (lilac). The range and type of terpenes that develop is highly influenced by the terroir the grapes are grown
- Range of sweetness levels.
from bone dry to lusciously sweet. Thanks to its high natural acidity Riesling is able to handle residual sweetness better than many other varieties. Is also susceptible to botrytis
- Low to moderate alcohol levels
a result of the cooler climates (or earlier harvest) typical for Riesling. Also, ferment is often stopped before completion to retain some balancing residual sugar. However, some Grand Cru Riesling from Alsace can breach 14%
helped by innate fine acid and delicate fruit and floral characters that are typically preserved through gentle, anaerobic, low solids winemaking with a general avoidance of malolactic fermentation and use of new oak
- Light to medium bodied
cooler climate or early harvest. Usually low solids winemaking to emphasis fruit expression. Again, some Grand Cru Riesling from Alsace would be considered full bodied
- Combination of lightness and intensity
potentially a result of a high concentration of terpenes and high acid combined with anaerobic, low solids winemaking and general avoidance of new oak and malolactic fermentation to emphasise aromatics and fruit
- Low level of wine making influence
most Riesling winemakers want to emphasis purity of fruit and therefore generally avoidance of new oak and malolactic fermentation
- Petrochemical notes (kerosene), especially with aging
a well studied area of Riesling but still don’t have all the answers. Sun and temperature a major contributing factor though. High levels of kerosene-like aroma can be used as a marker for warmer climates. This aroma also increases with bottle age. The Australian Wine Research Institute have a good article on the subject.