I am not lying to you, swirling a glass of wine actually does something. Surprisingly, some might say, it is not an aid to help you appear more sophisticated amongst your compatriots. There is a term that applies to what is happening when you are swirling a glass of wine.
“Volatizing the esters” produces the interesting aromas and bouquets in the wine that are so appealing to our nose. And since what you smell is also about 90% of what you taste, you’re going to want a wine that smells good to you.
Once the grapes are crushed and put into fermentation tanks, oxygen doesn’t touch the wine again until it is in your glass. When oxxygen finally mixes with the wine, a chemical reaction occurs that releases the flavors and aromas that you experience. This is why, as I’m sure you’ve heard before, you should let your wine sit for a little while after it is opened so it can “breath.” (See previous article on Decanting)
Be careful with how vigorously you swirl lighter whites, like Sauvignon Blanc, Riesling, Gewürztraminer, etc. Some wines can be somewhat fragile and over-zealous swirling could cause them to lose some of their more delicate nature.
For the most part, now you know a little something about why people do this charming little thing at restaurants and wherever else they might do this. Wineries I suppose? Caution is advised when wearing white.