An Aromatic Grape Variety
Riesling is an aromatic grape variety. As a young wine, Eden Valley Rieslings typically display bright and fresh aromas of lime / lemon, white floral blossoms, green apple and savoury hints of sage and thyme, backed by vibrant acidity. On the palate the zesty citrus is the pillar of the flavour profile – predominantly Meyer lemon and lime juice, some with hints of grapefruit, lemon peel or lemon pith, with a backbone of minerality.
In combination, the citrus flavours and minerality deliver a range of textures and flavours. The sense of lemon sherbet / lemon sorbet is born of the interplay between the brisk acidity and the minerality, with expressions of talc, bath salts and quartz often evident, combining in a mouth-feel often described as slate or wet pebbles. Savoury elements are usually subtle, with hints of spice, ginger and sage evident in some wines. The structure is typically pristine, with the best Rieslings showing wonderful mouthfeel, intensity and purity, incredible balance with both power and elegance, texture and length.
Riesling has higher natural acidity than many other varieties, and it is this acidity that makes Rieslings so wonderfully vibrant when young and delivers the structural integrity to age beautifully; longer than many other wines.
The best Rieslings can enjoy a very long life – some for many decades. However, a mature Riesling will display different characters to a young wine. As they age the palate broadens, and the bright fruit of their youth evolves. Citrus remains dominant; typically, the fresh lime develops to a richer, glacé like character, some with undertones of mandarin, while the lemon takes on some richer marmalade flavours.
Age adds complexity; older Rieslings will be dryer on the palate, fuller and richer, displaying characters of preserved citrus, lemon butter, nuttiness, toast, biscuits, honey and beeswax; the acidity and minerality remaining the structural backbone, keeping the finish long and vibrant.
At 2 to 3 years of age, Rieslings start to show hints of their secondary characters, and over the next few years they will display both primary and developed characters. It is a wonderful evolution. Great wines will show their age through their increasing complexity and yet can still look youthful well into their second decade, and for some, far beyond.
The vibrant beauty of young Riesling is a great match to many foods, and as Rieslings age the list of pairings only grows.
Young Rieslings are perfect aperitifs. Their citrus minerality is a great match to oysters, shellfish, white fleshed fish, sushi, sashimi, grilled octopus, Asian cuisine, aromatic dishes, poultry and white meats.
More mature Rieslings pair beautifully with richer foods such as veal, roast pork, pork belly, duck, game meats, roasted vegetables and darker fleshed fish such as grilled tuna and swordfish, and match brilliantly with goats’ cheese, semi-hard and aged hard cheeses.
The high natural acidity of both younger and older Rieslings pairs beautifully with rich, creamy sauces, the clean crisp finish cutting through rich foods to cleanse and refresh the palate.
Riesling excels with spicy foods. From green chicken curry to spicy paellas, peri peri prawns, Portugese chicken, red duck curry – the list goes on.
The Elephant in the room – ‘Petroleum’ characters
Older Rieslings can show an aromatic character that is sometimes described as ‘petrol’. In the Northern Hemisphere, this term is used to reinforce quality, while in Australia it can be seen as a negative trait. A discreet amount of this character can enhance the wine, while too much can be less appealing. The character can also be described as kerosene, paraffin and oily.
This aroma has been identified as trimethyldihydronaphthalene, created by the breakdown over time of Rieslings principal ‘fruit’ aroma compounds called terpenes. The characteristic is exaggerated by excessive phenolic compounds.
The degree of this character can be limited through viticultural practices and winemaking choices, including good canopy management to limit sun exposure and sunburn, picking at optimum ripeness (avoiding over-ripeness), limiting excessive water stress and using only free run juice in winemaking.
As this is an aromatic character it is not so evident on the palate, and once poured and exposed to a little air, most of this character dissipates, and the beauty of a mature Riesling will unfold.
NB: See the Notes below for more information of TDN, Terpenes and Phenolics.
There’s a beautiful aroma you find in old, well-cellared bottles of Riesling, one that is deliciously distinctive but hard to describe. If you’ve ever stuck your nose into a glass of good, 20-year-old Eden Valley Riesling … you’ll know the aroma I’m talking about. It’s sweet, like candied citrus peel or mandarin syrup, but savoury, too, like buttered toast. It’s a bit earthy, like button mushrooms. And oily and evocative, like faded sandalwood. But … it’s not really like any of these things. It smells of itself: lovely old Riesling perfume.
“The ‘aged’ character in Riesling is linked to the formation of the compound TDN (1,1,6-trimethyl-1,2-dihydronaphthalene). TDN is created from flavour compounds called terpenes by acid hydrolysis. TDNs increase in concentration when grapes are exposed to sunlight and warm temperatures. High concentrations of TDN are also linked to bottle age. To reduce TDN levels, modifying canopy density early in the season can be effective; where possible, grapes should be harvested from cool locations; in warmer years, consider harvesting earlier.” – AWRI Report
Rieslings aroma intensity correlates with the terpenes concentration in the wine. These are aroma compounds found in the essential oils of plants. Rieslings varietal aromas are determined by a small number of terpenes. These are found mostly in the skins, and the concentration increases as the grapes ripen.
Terpenes are chemically bound to grape sugars and are odourless in that form. Around
a quarter are freed up during the winemaking process, through fermentation, time on lees and bottle aging.
The major terpenes found in Riesling are: Linalool (Rose aroma), Alpha-terpineol (lilac), Citronellol (citronella), Nerol (mandarin), Geraniol (grapefruit) and Hotrienol (Lime).
The concentration of these decrease as the Riesling ages, while other derivatives increase with age – creating Riesling’s more developed secondary characters.
Phenolic compounds in Riesling have a bearing on the development of the ‘harder’ aromatic and textural characters. Phenols increase with exposure to sunlight and are present in pulp, skin and seeds. In higher concentrations Phenols contribute astringent, oily and bitter characters. While phenolic characters are desirable in many wines, they are less desirable in lighter aromatic wines – Rieslings in particular.
To reduce the amount of phenols in Riesling, good canopy management to limit sunburn on bunches is important, as it the choice to use free run juice, limiting the phenol extraction from skins, pulp and seeds. These management practices will also reduce the levels of TDN, and in turn minimise the development of the more aggressive ‘petrol’ characters.