Overripe red wines lack fresh aromas, have low reductive strength, develop pruney aromas and fail to age well. In technical terms, the degree of oxidative polymerization of the tannins has proceeded on the vine to an excessive extent. It might be said that the wine has run down the chemical battery it normally uses to protect itself from oxygen during ageing in barrel and in bottle and to defend itself from oxygen-loving microbes like Acetobacter, or vinegar bacteria. High ripeness also tends to be associated with high pH, which is the “gas pedal” of ageing, and controls the rate of oxidation of many wine constituents. Such “over the hill” wines tend to brown early and their tannins dry out — that is, they become grainy and move from the top of the tongue to under the tongue and into the cheeks, giving a dirty impression which obscures flavor perception. The tannins have essentially curdled, and just like a botched bearnaise sauce, they fail to integrate aromas. As a consequence these wines show, along with oxidative notes of caramel and prune, also disjointed aromas of oak, vegetal notes and microbial smells, which then protrude in the nose in unpleasant disarray.
On the other hand, sometimes grapes achieve very high brix without these problems. A case in point is the 1999 CSU Fresno Syrah in our study, which came in on September 17th at 31 brix, but possessed fresh blueberry aromas and fine, firm tannin, and is still drinking quite well today. So high alcohol per se does not necessarily indicate overripeness. This wine was, however, quite hot on the palate, and the high level of alcohol caused a bitterness in the finish and also exacerbated the astringency of the tannins. When we adjusted the alcohol down to the normal range, these imbalances disappeared, and the wine did well in competitions and aged well.
Not so the unadjusted 18% wine, which more rapidly developed raisiny notes, browning, and oxidation. A dozen or so trials over the years have shown us that high alcohol wines develop differently than their counterparts in which we have reduced the alcohol, wines with exactly the same composition of color, flavor and tannin. We often see zinfandels developing raisiny notes more rapidly at higher alcohol, for example.
We don’t know why this is happening, but our recently enhanced understanding of the nature of wine offers clues. The answer may lay in the weakness of high alcohol wines to preserve macromolecular structure. GrapeCraft contends that the color and tannin molecules in red wine aren’t soluble in its 13% alcohol solution. They can only leave the skins if carried into the fermenter, and eventually into the glass, by suspended tiny tarry colloids – liquid chocolate, if you will.
The Vineyard Enologist is the skilled chef on the scene who is concerned on a weekly or sometimes twice-weekly basis with monitoring vine water pressure, soil life, and berry sensory maturity. Her presence also facilitates observations of insect ecology, disease pressures and other contingencies.
The term “Vineyard Enology” was coined by Kay Bogart, who remains its foremost practitioner, a solid GrapreCrafter extraordinaire, and also has her own Bogart label for which she produces, from 120 year old Cinsault, a remarkable red wine as well as a dry rosé named Beautiful Friendship, the last two words of Bogie’s Casablanca.