The nose knows

As you start exercising your sniffer, you may be able to distinguish between different types of aromas in wine. 

In an earlier post about decanting, I made a distinction between aroma and bouquet, but I didn’t tell you where the aromas come from. 

There are three different types of aromas; primary, secondary and tertiary.

1. Primary aromas or varietal aromas: originate in the grapes and vary according to the vine or the terroir.  These aromas are an expression of viticulture and cover fruity and floral nuances.  Two good examples are the grapiness of wines made from Muscat grapes (linalool and citronellol molecules) and the green pepper aromas in many Cabernet varieties (2-methoxy-3-isobutylpyrazine). 

2. Secondary aromas or pre-fermentation and fermentation aromas: come about from both alcoholic and malolactic fermentations and vary according to maceration time, fermentation temperatures and yeast strains used.  These aromas are created by microorganisms, as sugars and amino acids are transformed.  An example would be the hazelnut and butter aromas that often show up in Chardonnay (diacetyl formed during malolactic fermentation). 

3. Tertiary aromas or post-fermentation and maturing aromas: primarily derive from oxidation in barrel-matured wines.  Simply put, these are aromas that are a result of aging.  As they age, white wines take on aromas of dried fruit and red wines take on fig and prune notes.  As wood tannins in the barrels break down, they can impart many aromas; vanilla, coconut, butter (diacetyl), cloves (eugenol), leather (4-ethyl-phenol) and almonds (furfural).  Here’s a list of other common tertiary aromas: mushroom, truffle, liquorice, caramel, coffee, chocolate and smoke. 

Faults, like vinegar or rotten eggs, can happen at any stage in the game, but we’ll save that for another time.  Happy smelling!