Flowers can brighten a room or brighten someone’s day. They have been contemplated for their beauty in painting, poetry and prose throughout the ages. They have graced gardens the world over for centuries. Their aromas have inspired the scents of perfumes, potions, soaps, candles and essential oils. But what about floral aromas in wine?
It may come as a surprise that floral aromas are almost always present in every wine. Some more than others of course, and one has to take into account that stronger, more intense aromas may overpower, and even sometimes outlive, the more delicate, subtle aromas of flowers. However, it would be an interesting experiment the next time you taste a glass of wine to ask yourself not if there are floral aromas, but what floral aromas there are.
As a general rule, these aromas tend to align with the colour and age of the wine. For example, in young, white wines aromas of fresh white flowers are common, such as orange and apple blossom, jasmine and white roses. Likewise, in young, red wines aromas of fresh violet and red flowers are common, such as violets, iris, and red roses. Aged white wines orient more towards yellow flowers like camomile, acacia and broom flowers, while aged red wines take on aromas of dried flowers and potpourri.
Primary, Secondary and Tertiary Aromas:
Crucial to understanding where wine aromas come from and how they evolve over time is the division into three categories: primary, secondary and tertiary.
Primary aromas derive directly from the grape. They are located mostly in the skins and belong principally to the chemical group of terpenes which are responsible for predominantly floral aromas. These aroma molecules present in the grapes are also found in the must during the fermentation process and the resulting wine, producing aromatic and semi-aromatic wines with highly recognisable aroma profiles.
Aromatic grapes include:
Semi/aromatic grapes include:
- Sauvignon Blanc
- Cabernet Franc
Secondary aromas are formed during the fermentation process. These can be broken down into aroma molecules that are formed pre-fermentation and post-fermentation. When the grapes are crushed before fermentation, the molecules present in the grapes are transformed by enzymes, producing volatile alcohols and aldehydes which give off a vegetal aroma. During alcoholic and malolactic fermentation, the molecules continue to break apart and transform, producing volatile esters, higher alcohols, aldehydes and acids characterised by fragrant floral and fruit aromas common in young wines.
Finally, tertiary aromas arise from the evolution of the wine either in wooden barrels or in the bottle. They are formed thanks to a variety of processes including oxidation, acetilization, esterification, etherification, as well as the transformation of tannins, alcohols, acids, esters and other phenolic compounds. During the evolution of a wine, primary and secondary aromas tend to diminish or otherwise evolve. For example, fresh flowers evolve into aromas of dried flowers and potpourri while fresh fruit evolves into aromas of mature, stewed or confetture fruit. Tertiary aromas begin to take over and are characterised by notes of dried nuts, leather, wood, liquorice, spices and other toasted, animal and ethereal aromas. In general, the bouquet of aromas becomes more complex as well as homogeneous, cohesive and harmonious as the wine ages.
Pure and Linked Terpenes:
While the classification of primary, secondary and tertiary aromas can help create a sort of sensorial map for identifying where aromas come from and how they evolve, a further look into chemistry can shed light on the nature and expression of floral aromas specifically.
Luigi Moio, in his book “Il Respiro Del Vino” eloquently describes how our noses are able to “see” things which are invisible to our eyes, referencing a quote from Antoine de Saint-Exupéry’s “The Little Prince”:
When we put our noses to the glass and inhale, the aroma molecules present in the wine create a sensation received by the receptors in our nasal passages. These receptors send the information from that sensation to our brains which process it, creating a mental image of what we smell and identifying the aroma. Our ability to identify the aroma depends as much on our experience of smells perceived throughout our lifetime as our ability to remember them by putting the pieces together to form a mental image. The next time you smell a glass of wine pay attention to the moment you identify an aroma and if you do, in fact, “see” it in your brain. Or conversely, notice if seeing a flower reminds you of its scent.
As mentioned before, the chemical class of terpenes are predominantly responsible for floral aromas, but not all terpenes are created equal. Some are pure, freed from bonds with other molecules, while others are linked. The higher the concentration of pure terpenes there are in a wine, the more intense the floral aroma will be. This is true for some young wines, especially white, however the freshness and intensity of the aromas tend to diminish in time as the molecules naturally disintegrate. On the contrary, linked terpenes are slowly released from their bonds with other molecules through a process of hydrolysis, conferring their floral aromas with the passing of time, sometimes even outliving esters and their fresh fruit aromas. This is often the case in some red wines.
Another interesting fact that Moio points out in his book is the dynamic nature of our scent perception, as put forth in the research of Rita Pessina at the University of Naples and the French Institute. In her research, Pessina measured the temporal dominance of sensation of six aroma descriptors in white wine: white-fleshed fruit, exotic fruit, dried fruit and nuts, floral, honey and boisé. Her studies showed that the retronasal aromas of white-fleshed fruit are perceived immediately and reach the maximum intensity around 10 seconds, persisting for another 20. Exotic fruit and floral retronasal aromas, on the other hand, reach their maximum intensity around 15-26 seconds, with floral aromas persisting for more than 40 seconds. So, another experiment for you, the next time you taste a glass of wine try breathing out from your nose and notice the aromas you perceive and how long they each last.
On a final note, another reason to stop and smell the roses is the fact that the part of our brain linked to scent is also linked to memory and emotion. Enjoying the pleasures of scent can produce neurochemical substances such as serotonin, enkephalins and adrenaline providing feelings of well-being, euforia, serenity or excitement.
Gho, Paola and Ruffa, Giovanni. Il piacere del vino, come imparare a bere meglio, Manuale Slow Food. Slow Food Editor, 2014.
Moio, Luigi. Il Respiro del Vino. Mondadori Libri, 2016
*Both are Italian books, which means I’ve translated some of the terminology so please forgive any imperfections. I’m not sure if they are available in English, but I can recommend “The Secret of Scent” by Luca Turin, an Italian biophysicist who illuminates the world of perfume just as poetically as Moio does for wine.
That’s a great post Danell, interesting, comprehensive and elegant too. You’ve put it together extremely well and I’m trying to save it in Pocket for reference. In a couple of weeks I’ll reblog it.
In recent years I’ve learned about and started to notice retro nasal smell, a revelation and it’s added lots to my sensory ability. I’m going to read your post again now …. so much chemistry!
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Thank you very much Dr. B! It is a lot of chemistry, things I would have never been able to understand if it hadn’t been for Luigi Moio’s book. The “hidden” world of molecules is truly fascinating! As are retro nasal aromas, revealing hidden layers to the wine.
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