Good / Bad Vintages - What Are They?

In class last week we briefly talked about "good" and "bad" vintages in Bordeaux - but what does it mean to be good or bad? I did a little research to address the factors that impact vintage, the consequent flavor profile, and ways winemakers can cope with less desired vintages.

According to Denis Dubourdieu, professor of oenology at the University of Bordeaux, there are five main criteria for a great vintage (1):

"1. An early and rapid flowering and a good fecundation assuring a sufficient yield and the hope of a homogenous ripening
2. Sufficient hydric stress at fruit-set to limit the growth of the young berries and determine their future tannic content
3. Cessation of vegetative growth of the vine before colour change, imposed by limited hydric stress and therefore allowing all the goodness from the root to flow into the grapes and not unproductive growth
4. Complete maturity of the grapes (sugar content among other factors) assured by the optimum functioning of the canopy (leaves) up to harvest time without further vegetative growth (point 3)
5. Good weather during vintage without dilution or rot, allowing full maturity of all grapes including late ripening varieties"

Translating the winespeak back to English, the key points are 1) early and rapid flowering, 2) lack of water when grapes start to grow in early summer, 3) vine shoots stop growing before grapes change color, 4) adequate heat and sunlight for full maturity of grapes, and 5) not too much rain. As you have probably guessed, the key to a "good" vintage is conducive weather conditions that help grapes grow and concentrate their growth in the ripening of the grains (i.e., not waste energy on growing the vines). 

So how does vintage quality affect how a wine would taste? Well, in poor vintage years, the grapes would not get enough energy and nutrition during its growth months in the summer to fully develop, or weather conditions in the fall become too harmful and the grapes need to be harvested prematurely. Therefore, wines made in poor vintage years generally lack intensity and complexity that one would find in better years, and the flavor profile has less potential to develop as the wine ages. 

However, there is also a different school of thoughts. Prof. Roman Weil at the University of Chicago conducted an experiment where 270 wine tasters were asked to judge bottles from various vintages that are accessible to the general market (~$20/bottle), and interestingly, the tasters couldn't tell the good vintages from the bad ones except for Bordeaux wines (2). The outcome corroborates with the popular belief that Bordeaux wines are more subject to weather conditions due to the volatility in its climate, but vintage might not matter that much for other regions, especially for wines that are not meant for long-term collection.

Finally, it's intriguing to think about what a vintner could do when the weather fails to cooperate. A common strategy in a bad vintage year for winemakers is to be more selective during harvest and reduce yield. A famous Tuscan wine maker named Piero Talenti was quoted saying "there are no bad vintages... there are just vintages in which we make less wine." (3) Another strategy, surprisingly, is to convince merchants that a bad vintage can improve with time. A Wine Folly article quoted US 2011 vintage as an example: it was considered a very cool and therefore unimpressive vintage, but the wines made in that year turned out to have higher acidity, and those made from prestigious winemakers were believed to have superior aging potential as a result. (4) 

In conclusion, vintage is probably more helpful for wine collectors, especially those who focus on regions like Bordeaux that are more susceptible to volatile weather conditions. Meanwhile, the $20 bottle of 2015 Bordeaux (a great year) we got from Costco might not taste that different from the 2012 one (a mediocre year). 

Sources: 

(1) http://www.decanter.com/learn/what-makes-a-great-vintage-276820/

(2) https://www.huffingtonpost.com/2015/03/03/wine-year-important_n_6784400.html

(3) http://www.boulderwine.com/wine-blog/why-bad-vintage-good

(4) http://winefolly.com/update/the-anatomy-of-a-bad-vintage-for-wine/