Ripeness, Style, Nature, and History
There is no single definition for the right degree of ripeness. Ripeness per se does not exist outside of the winemaker’s intentions about food functionality, fruit-forwardness, flavor density, structural integrity, and longevity.
The Loire appellations have become known for chenin blanc picked in three styles (remember, my convention is to capitalize the names of varietal wines and lowercase the names of grapes). The crisp, fresh, floral wines of Vouvray are gathered in early maturity before the mown hay/summer meadow notes of Savennières develop. Coteaux du Layon requires extensive hang time and botrytis to produce its honeyed vins liquoreux. Heat summation and season length to some extent dictate what can be done, but doubtless Vouvray-style wines could also be made in warmer upstream areas. In California, where no regional régisseur is looking over one’s shoulder and there is no fear of rain, we can do as we choose, targeting an off-dry, stainless steel–fermented quaffable wine for mass appeal or a complex sur lie, barrel-fermented, age-worthy Chenin Blanc aimed at the connoisseur.
In reds, control of tannin polymerization is a core postmodern skill. In determining ripeness, attention is centered on creating a good concentration of unpolymerized anthocyanins in the finished wine that will restrict tannin polymerization, leading to wines with finesse.
Optimum ripeness is a complex determination. Underripe grapes may not contain the optimum concentration of anthocyanins, may be difficult to extract, and also may lack desired fruit flavor density. Cellular breakdown in the skin, which releases pectinases that greatly aid extraction by reducing pulpiness and releasing pigment, may not have occurred. Malic acid reduction occurs throughout ripening and is advantageous to mouthfeel because excessive acidity overstimulates salivary response and brings excessive protein into the mouth, leading to coarse mouthfeel.
These difficulties pale in comparison to the perils of overripeness. To work well in the cellar, the reactive potential of tannins and anthocyanins must be protected from field oxidation. We are trying to make a tannin soufflé, and if the eggs are already scrambled, there is nothing that can be done in the kitchen. The tannins that result from excessive hang time are not stable and will become grainy and dirty in short order, imparting neither antioxidative strength nor aromatic integration to the wine.
Field oxidation also robs musts of monomeric anthocyanins. It is not enough to have good color; the color must be unpolymerized so it is still reactive and able to fulfill its role as a cap on tannin chains. High pH associated with extended hang time will also suppress the rate of pigment stabilization through aldehyde bridging (which is mediated by its low-pH carbo-cation form), instead promoting browning.
Sugar metabolism and the vagaries of raisining and dilution from dew and rain have little to do with maturity, and brix is an unreliable maturity index. It is a reliable guide to eventual alcohol content, but as we shall see, elevated alcohol is an enemy of color extraction.
Coextraction
In 1974, Pascal Ribéreau-Gayon published a color plate that revealed a mysterious reality: by themselves, anthocyanins are not very soluble in 12% alcohol and confer only a light pink color.3 If wine is a solution, red wine is not possible. He then showed how, in combination with tannins, the anthocyanins become deep red. Although no one knew what to make of this at the time, he was really demonstrating that color and tannin together form colloidal structures.
Recent enlightenments on the nature of extraction invite us to forget everything we thought we knew on the subject. Most winemakers concentrate on the methods of extraction: pumpover vs. punchdown vs. délestage; vigor and frequency of mixing; temperature; use of pectinolytic enzymes; and so forth.
In 2001, Roger Boulton published a review of a decade of research on copigmentation that revealed winemakers were barking up the wrong tree.4 Unless a home is provided for anthocyanins to extract into, no amount of punching down, pumping over, enzyme treatment, or temperature adjustment will result in stable color extraction. Boulton’s revelations concerning the makeup of copigmentation colloids showed that a color molecule was not going anywhere unless it could pair with another similarly shaped but uncharged monomeric tannin molecule, a “cofactor.” Anthocyanins can’t form into colloids by themselves because they have a positive charge and repel one another (fig. 4).
FIGURE 4. Configuration of anthocyanin vs. catechin vs. quercetin. The four bonds of carbon atoms assume a tetrahedral arrangement in 3D space. If, however, one of the bonds for every carbon in the molecule is a double bond, molecular configurations such as anthocyanins can lie entirely in a plane, stacking tightly with other planar flavonoids. The common skin and seed flavonoids are not planar and make so-so cofactors. But the UV protectant quercetin is planar, thus empowering it as a “super-cofactor” for extracting color into copigmentation colloids.
Anthocyanins belong to a class of phenolics called flavonoids, which are composed of three six-member rings hooked together. The most abundant flavonoids in skins are called catechin and its isomer, epicatechin. Unlike anthocyanins, however, these flavonoids aren’t ideal cofactors because they don’t lie flat. They’re lumpy. When exposed to moderate sunlight early in the season, grapes produce a UV protectant called quercetin, which is a more planar “super cofactor.” Boulton showed that these extractive “copigmentation colloid” intermediates are entirely composed of monomers. Oxidatively polymerized tannins resulting from extended hang time do not assist extraction, nor do most oak tannin products.
Boulton’s findings elucidated the wisdom of the practice of field blending and cofermentation of varieties practiced in many European appellations, where tannic whites are included with well-colored, tannin-deficient reds: palomino with garnacha in the Rioja, viognier with syrah in the Rhone, trebbiano with sangiovese in Chianti, as well as the interplanting in old California vineyards of small amounts of petite sirah, carignane, or alicante bouschet with zinfandel, barbera, or mataro (known now as the uptown “mourvèdre”).
In optimizing coextraction from other sources, gallic acid, a breakdown product of ellagitannins from oak, is an excellent cofactor. It is not available from the surface of toasted oak barrels, staves, chips, or dust but only from untoasted oak that has not been heated or sawn. But beware: untoasted oak typically contains the planky aromatic defect trans-2-nonenol. Unless carefully air cured in a manner that does not build up TCA (2,4,6-trichloroanisole, the moldy aroma also associated with corkiness), untoasted oak can ruin a fermentation. Thus it should only be purchased from a reputable supplier and used immediately.
Copigmentation colloids are not stable. If young reds are deprived of oxygen, they can lose their color almost overnight, and dry, grainy tannins will result. Since water polarity is the driving force holding the colloids together, copigmentation does not occur at all at 20% alcohol, and thus precipitation may even take place near the end of high-brix fermentations—another peril of extended maturity. Bitartrate crystals may also take up pigment and carry it into sediment.
If one follows a methodology to encourage vine balance, to harvest ripe but not overripe, and to provide material in the must for coextraction, the elements for graceful aging will be present in the young wine. We have bought ourselves a ticket, but we have not arrived. In fact, if the fruit is exceptional, we have now created a monster: aggressive, reductive, and quite unpleasant. Taming this beast, feeding its appetite for oxygen, will provide the driving force for our tannin soufflé. Judicious blending and proper oak choices are best made immediately. The ins and outs of élevage technique are the subject of the next chapter.
TAKE-HOME MESSAGES
A fruit-forward impact wine compares to a reserve-style vin de garde as a pop fly compares to a line drive.
Winemaking is a branch of cuisine—the ultimate slow food—and has much in common with the making of sauces, because the soulfulness of flavor integration is a result of refining its structure.
Oxygenation at this early stage does not shorten the