Pinot Noir Color


Dear Clark:
I met a wino a few weeks ago who spouted a term at a lecture that described the color deficient qualities of Nebbiolo, Pinot noir and Grenache. He said that they were all "monosomething saccharides". Do you know what the term is (and, hey, do you agree with him)? 
PS: Great piece on PSs.


Dear Patrick:

I imagine that the term might have been “non-acylated monoglucoside anthocyanins.”

I am not aware that Nebbiolo pigment lacks acylation, but it certainly accounts for some of the peculiar color difficulties of Pinot Noir.

All Vitis Vinifera are monoglucosides (the di-saccharide pigments, illegal in Europe, mark American genera), so that part is no big deal.

This means that unlike most other flavonoid phenolics (that’s the familiar three-ring circus of chicken wire you see in all the books), anthocyanins have a fragile structure which is stabilized in the grape somehow by enzymatically tacking on a glucose sugar molecule on the “C” ring, the one in the middle containing an oxygen molecule. This glucose protects the molecule from falling apart, but is itself a highly edible goodie which is vulnerable to attack by lots of enzymes from yeasts and other microbes. So the grape in most varieties tacks an acetic acid (vinegar) molecule onto the sugar to put a big bump on it which makes it fit poorly into the active site of the yeast enzymes which are trying to attack it. Tacking on a protective acetyl group is called acylation.

Pinot lacks acylated pigments.

The other way to stabilize pigment is to incorporate it into a polymer. This takes time, so the pigment is most vulnerable in the fresh wine. It’s important to get pinot to settle clear and let it see a tiny bit of oxygen when it’s young to stimulate oxidative polymerization. Unfortunately, unlike Cabernet and Petite Sirah, Pinot Noir doesn’t readily fall clear because it lakes tannin to fine down the yeast turbidity, so it’s doubly vulnerable.

Another problem Pinot has is that it is deficient in copigmentation cofactor. Anthocyanins aren’t soluble in 13% alcohol, so they need to be extracted into little beads called copigmentation colloids. But they are positively charged, so they repel each other and won’t form beads. Thus there need to be other monomeric phenols which will help glue the bead together. Pinot Noir in most weather conditions (except, say, the Sonoma Coast) is very low in these cofactors, so its pigments won’t come out easily. This is also true for Nebbiolo in most regions, which is what makes Barolo so special.




mark bunter:


Pinot, and the other weaklings mentioned, are only "deficient" compared to other grapes. When all wines have the color of Alicante, the aroma of Merlot, the flavor of Argentinian Malbec, and score 97, I, for one, will find wine boring. Maybe I just lack imagination, myself, and find relief from my own psychic banality in varied external sensory stimulation. No doubt my chemistry is deficient, well-acylated though I be. If one prefers dark wine, so be it, but that doesn't mean other manifestations of Vitis vinifera aren't worthwhile.
I think many winemaking moves are tradeoffs. It is useful to know that a little oxygen in a Pinot's childhood will help its color, but the result of more lees contact and less oxygen seems worth the trade, to me. Perhaps a subtle change like some new thin stave cooperage could serve as a compromise? This game is wonderfully subjective. I also have seen a wide range of fermentation and post-fermentation practices that result in varying exposure to air- but can I correlate them with color? Hmmm... Thanks again for concise explanations of complex and critically important winemaking phenomena. Mark

I'm afraid I am not expressing myself well. It is not darker pinot that I am supporting, but good stable structure. The importance of color to structure is that anthocyanins are terminals to polymerization. Without color, tannins lengthen and become dry, as is so often the case with pinot. Lees contact to young pinot aggressively attacks color and makes this situation worse. Certainly most pinot is too fragile to tolerate exposure to oxygen except with great skill and a gentle hand.

mark bunter:

I think you were clear. The original query involved deficient color. Your comprehensive knowledge of many of the chemical processes involved here certainly exceeds mine. I'm not arguing, my point is that some winemaking choices, like not racking most Pinots, create wines that I LIKE. I am grateful to you for helping me to understand why those choices may contribute to lighter color and different structure. In the past, I had never run into "dry" tannins in Pinot. My experience was limited to a few Napa vineyards, picked at moderate ripeness (meaning lower Brix, usually, higher acid, lower pH, partly green seeds, etc). Now that I have had some experience with Monterey Pinots, of certain clones, left out to ripen more fully, by modern standards, I understand what you mean. Fortunately, this kind of fruit generally has more pigment, so it stands up to some oxygen. With respect to all these elements, my object is focused more on balance, flavor, aroma,interest, and individuality (minerality, terroir, whatever). I take whatever color I get. I don't mind if it's light. I guess I'm a little bothered by the contemporary obsession with color for color's sake. Color can indicate a lack of wine quality, but doesn't help predict the presence of quality. BTW, your monograph on SCM Pinot in Appellation America was excellent. I was sorry not to see any Martin-Alfaro wines (Corralitos) mentioned. I loved your classifications- "Ethereal", etc. Thanks. Mark