Impact Compounds in Wine

My wine notes, like others, frequently include aroma and flavor descriptors (black cherry, rose petals) that may seem fanciful and unnecessary. As one of my friends put it, "It just smells and tastes like wine." A recent post from Wine Folly explains how these descriptors give you a road map to the grapes and processes used to produce the wine. They are, in effect, a chemical profile of the wine which doesn't necessarily define quality as much as your personal tasting preferences.

Of more than 100 aroma compounds in wine, according to the article, there are six that play an impactful role. PYRAZINES (methoxypyrazine) are found mostly in Bordeaux varietals--Cabernet Sauvignon, Cabernet Franc, Merlot, Malbec, Carmenere and Sauvignon Blanc. It's a smell that is almost unmistakeable in Sauvignon Blanc: bell pepper, freshly cut grass, asparagus, celery and green peas. When it appears in red wines, it is not always considered agreeable. Robert Parker consistently marked down Cabernet wines with obvious green tones, and he influenced many tasters, including me. Fortunately for me, this green tone usually disappears, replaced by a cherry note, after many years of aging. I have many well aged Bordeaux and Napa Cabernet wines that I love, but I find most young Cabs (and particularly Merlots) with green tones virtually undrinkable.

Pyrazine I cn do without. ROTUNDONE is my holy grail. It creates the black pepper, spice (marjoram, rosemary, thyme), earth and old leather that is common in wines made from Syrah, Grenache, Mourvedre, Aglianico.and Zinfandel grapes. That is why my tastes run toward the Rhone, and particularly the Southern Rhone plus certain areas of Italy. Unfortunately, studies have found that 20 to 25% of the population cannot smell rotundone. The majority of those who can report it as a positive smell. 

The other impact compounds listed by Wine Folly are:

 SOTOLON (maple syrup, grilled nuts, figs, honey) that is created by oxidation in wines such as Sherry, Vin Jaune, old Sauternes, old Chardonnay and very old red wines;

TDN or petrol that is most prominent in Riesling but also in some Chardonnays and other white wines;

DIACETYL, which is responsible for the buttery, creamy flavors and textures in wines, red and white, that have undergone malolactic fermentation; and

MONOTERPENES (roses, flowers, sweet spices, mandarin orange), which are dominant in Muscat Blanc, Gewurztraminer, Viognier but also some red wines such as Nebbiolo and Pinot Noir.

The interaction of these compounds and others creates the complexity and interest of any wine. If the wine simply tastes like wine, you may be missing or ignoring these compounds. Or the wine may just be a simple wine.