People often describe wines as having different aromas. One might say, “This wine smells like strawberry, mushroom, eucalyptus and black tea.” What makes a wine smell like a specific fruit or earth tone… does the winemaker throw other fruits or flowers into the tank of grapes while they are fermenting? We have heard this question a lot from those just discovering the world of wine, and the answer, simply put, is “No.” The geekier answer is “Aroma Compounds.”
Aroma compounds can be defined as “chemical reactions during fermentation and aging which determine the way a wine smells.” Certain aromas are released due to characteristics of a specific grape type, while others are a result of reactions during fermentation (yeasts) or the oak barrel the wine was aged in.
There are different types of aroma compounds in wines. Some may make the wine smell like fruit or white flowers. This specific type of aroma compound is called an ester
. Esters are formed during primary fermentation, malolactic fermentation and aging. If a Pinot Noir smells like strawberries, that is because the same ester that causes a strawberry to smell the way it does is present in the wine. If a Chardonnay smells like lemon blossoms or gardenias, this is also a type of ester. Conversely, you may smell earthy scents in a wine. Smells such as roasted beets, mushroom and leather are called geosmin
. Geosmin is also what makes the air smell the way it does after a fresh rain.
Have you ever wondered why a wine, especially Chardonnay, may smell buttery, creamy or even like coconuts? What you are smelling are called lactones
. Lactones are released during malolactic (secondary) fermentation and through aging in oak barrels. Another form of aroma compound is called terpenes
. Terpenes can smell sweet and floral to resinous and herbaceous. These aromas occur during fermentation, but are not produced because of the yeast. They are naturally-occurring aromas in the grape itself. Lavender, citrus, eucalyptus and florals are all examples of terpenes.
It can be tough to pinpoint specific aromas lifting from your glass of wine because so many different aromas meld together. Often your nose recognizes an aroma as familiar, but your brain has trouble finding the word to describe that scent. Don’t get frustrated, just start by trying to categorize it in your mind. If you smell fruit, is it citrus, stone fruit, berry, etc.? A Wine Aroma Wheel
can help you identify the different aroma compounds (and flavors too) so you can go further to say it’s lemon versus lime, or raspberry versus blackberry.
Happy research and happy tasting!