Your noses detect the wine aroma you taste in your mouths—one of the wine tasting basics often ignored by traditional wine tasting etiquette.
We had this conversation in a recent live tasting class.
Student: Are we tasting the aroma or are we smelling them?
Isabelle: Both, you are smelling the aroma when sniffing the wine, and tasting the aromas when the wine is in your mouth.
Student: So, it's in your mouth, and you're smelling it.
I'm always thrilled when my students realize the power and complexity of their sense of smell. I tell them often we should correct the word "wine tasting" by "wine smelling" because our nose detects the majority of what we experience by "tasting."
Note: I show you how to smell aromas in the mouth in a short video at the bottom of this article.
The origin of wine aromas is complex, coming from the grape variety, the fermentation, and aging processes. We perceive aromas through many mechanisms when tasting wine. Once you know what happens in your mouth, many perceptions make sense (pardon the pun), and so do good practices to enjoy fully wine aromatic nuances.
When you pour wine in a glass, you smell the most volatile aroma compounds, easier to detect by sniffing the liquid. Once the wine is in your mouth, it's warmed up to 37C (98.6F ); thus, the heavier volatile compounds have more chance to go airborne and reach your olfactory receptors through the retronasal passage.
But wine is a complex mix of components, some binding aroma molecules. These aroma molecules are smell-less. But they can smell when you sip the wine in your mouth.
A 2021 scientific review by Lyu and coll. describes nicely the different phenomena happening in your mouth, which allows you to perceive more aromas than you could just by nosing the wine.
So, a lot is happening in your mouth.
First, wine blends with saliva, a liquid made of acid, salts, and microbes. Saliva has the power to break down the bigger molecules, which bind aromas. Once freed, the small aroma molecules reach your nose via the retronasal passage.
Bacteria naturally present on your mouth mucosa or teeth gums can also break down wine components, releasing other aroma compounds.
That's why you can perceive different "smells" in your mouth compared to what you smelled directly from the glass of wine. New aroma compounds are freed in your mouth that you couldn't smell otherwise.
If you were taught that you have to taste the same aromas that you smelled initially, that’s inaccurate. Forget about it. Myth busted.
Some aroma molecules get trapped in your mouth epithelium. Sometimes, after you swallow the wine, aromatic sensations linger in your mouth. They are due to the trapped molecules finally released and reaching your olfactory receptors, through the retronasal passage, by the air you exhale.
And it can take several cycles of you swallowing, using your saliva to remove any remaining aroma compounds.
That's why it's critical to rinse your mouth between wine samples in a tasting flight. Aromas from wine A, bound to your mucosa, can be released when you're tasting wine B. You would describe wine B expressing wine A's aromas.
It's not an issue in the big scheme of wine enjoyment, but it's an issue if you're an analytical taster or wine judge asked to make fair assessments of different wines.
Research showed that most aroma compounds reach your nose with the first exhalation after swallowing the liquid, nicknamed by scientists the "swallowing breath."
I have described in other articles how our individual differences explain our ability to detect and describe aromas. Well, it seems that our breathing capacity is one of them. With superior breathing capacity (a high Vital Capacity-VC), some of us can release more wine aromas than those with weaker breathing capacity.
I noticed and measured through my sensory practice that people take 15 ml to 20 ml of wine in one sip. If you take a larger volume, you will perceive more aromas or these aromas are more intense than if you took 10 ml.
Using consistent sip volume is a good practice in a comparative wine tasting.
Maybe it's your practice to roll the wine in your mouth before swallowing. Rolling or chewing the wine aerate the wine to favor the release of free aroma compounds.
The saliva and bacteria in your mouth blend more efficiently with the wine and help release bound aroma compounds.
But doing so, you also allow some compounds to bind with your mouth mucosa. These compounds will linger in your mouth for you to enjoy.
Or they may remain at your detriment if you have many wines in a flight to judge.
Wine aroma compounds need to reach your olfactory receptors through the retronasal passage. But they need to be able to do so.
Wine is complex, and your ability to detect and appreciate specific wine aromas depends on many factors.
Try this simple exercise. I demonstrate it in this video (click this link).
Jiaheng Lyu, Shuang Chen, Yao Nie, Yan Xu, Ke Tang, Aroma release during wine consumption: Factors and analytical approaches, Food Chemistry, Volume 346,2021, 128957, ISSN 0308 146