“This wine smells amazing!”
Scientifically the sense of olfaction is enabled by chemical compounds that can volatilize in the air and perceived by the olfactory receptors located up in the nostrils. There are two ways that you can experience the “smell of a wine”. The first is directly through your nostrils when you inhale a scent and the second is through your retronasal passage, also known as the area in the roof of your mouth that leads directly to your nasal cavities.
Take a look at the picture from the book "Il Respiro del Vino", from Luigi Moio.
Here you can see that the nose is responsible for perceiving the so called “odours”, while the retronasal passage is responsible for perceiving the so called “aromas”. Together with the “taste”, they make up the wines' flavours. So, the perception of an aroma through the retronasal passage happens only after you taste the wine, where except for the 5 tastes that our tasting buds perceive, the aromatic compounds are driven to the retronasal passage. Here you can discover so many more aromas and consequently, flavours.
Usually people refer to “odours” as “aromas”.
Before you start swirling your glass, take a quick sniff of your wine to make sure it doesn't have any defect like cork, bacterial infection (ex. Brettanomyces bruxellensis) or if the wine is oxidized or reductive. If your wine is healthy, it's the time to swirl the wine around the glass. Swirling aerates the wine and releases its bouquet, letting your nasal cavity draw up the scents into your olfactory system, which is essentially the control panel for your sense of smell.
After you swirl, put your nose in the glass and take a gentle, but long and deep sniff and make a mental note of what you smell. Your olfactory interprets what you smell and compares it immediately with other familiar ones. Technically this is called 'the recognition threshold', and a good example of this is how a random smell can snap you back to a specific childhood memory in a flash.
Does the smell remind you of anything? Wine is made up of more than 300 different organic chemical compounds that are similar to those found in nature!!!
That's why specialists describe wines' aromas in terms of fruits, vegetables, herbs and spices.
The aromas in wine can tell you a lot about the variety, the age of the wine, the ageing & production techniques (barrel aged or aged on fine lees), the vineyard location and countless others.
To make the smelling stage of wine tasting a bit simpler we can divide the aromas in three big categories:
1) Primary aromas, which derive from the grape variety and growing region. Primary aromas are fruity, herbal, or floral.
2) Secondary aromas, which are produced by the fermentation process are any bread-like aroma. This is a result of the yeast used in the fermentation.
3) Tertiary aroma, which come from the ageing process. It’s more an evolution of the wine in bottle character. These evolved aromas may appear over time as nuttiness, smoke, or honey in whites, and as leather, tobacco, or forest ground in reds. This category also includes any oak treatment, which can produce different aromas depending on the oak used.
The first and easiest step to improving your wine smelling skills is becoming aware of the everyday smells around you. Start paying attention to smells you encounter throughout your day and try to identify them. Whether you’re outside, eating, lighting a candle, stop for a second and think about what’s in the scent and try to catalogue it.
Over time, exercising your nose will result in greater sensitivity and suddenly you will be surprised by how you will be able to identify aromas in the wines you are drinking!
So let's have a glass of wine and try to identify the odours and aromas in it! Cheers to life!