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The Problem with 'Physiological Ripeness'
By Paul Lukacs
Sep 1, 2020
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Ripe fruit tastes sweet, unripe fruit harsh and sour.  Think of a summer peach, an autumn pear or a spring strawberry.  So too with wine grapes.  Ripeness and sweetness go hand in hand.

Though people have understood this for many millennia, vintners have only associated ripeness with sugar for about 250 years.  The famous French chemist, Antoine Lavoisier, proved in the 1760s and 1770s that the sugars in grapes are the same as the sugars in other fruits and vegetables, and that fermentation converts them into alcohol and carbon dioxide.  (He could not explain, however, what causes fermentation.  Louis Pasteur did that almost a century later when he showed that living yeasts function as the catalysts in a process previously regarded as magical or mysterious.)  Thus, for vintners following Lavoisier, ripeness meant sweetness, and sweetness was determined by measuring the sugar content in the grapes.

All sorts of wines were made with this understanding of ripeness.  In bad vintages, or when winemakers picked their crop too early, many tasted unpleasantly sour.  At the same time, though, some of the greatest wines ever made were fashioned following this understanding.  Particularly following the Second World War, when oenologists, led by Professor Emile Peynaud from Bordeaux, emphasized the necessity of using only ripe fruit for the best wines, overall quality skyrocketed.  Some did have slightly green, vegetal undertones, and the reds were inevitably quite tannic, but alcohol levels remained fairly low, and acidity was usually high, so the wines tasted harmonious and complete. 

Nothing much changed until about twenty years ago.  That was when some oenologists and winemakers began talking about something they called “physiological ripeness.”  This did not refer to sugar, but rather to other factors that may yield a somewhat sweet or sour impression on one’s tongue.  Identifying this newly conceived form of ripeness required not just measuring one element but assessing a host of different elements, including the color and texture of the grape seeds, the pliancy of the skins, the consistency of the pulp, and more.  Doing so also required getting out of the laboratory and going into the vineyard, where one could literally taste the fruit on the vine.

This emphasis on physiological ripeness came mainly from people living and working in warm New World wine regions.  That’s because when vines are cultivated in sun drenched locales such as those found in much of California and Australia, sugar levels can rise rapidly.  The rest of the grape may remain somewhat immature, with green seeds, tough rather than soft skins, and unbalanced acids, but there will be plenty of sugar for fermentation. 

Before long, pursuing physiological ripeness became something of a grail for many vintners.  They declared, in what has since become a cliché, that “wine is made in the vineyard,” because they were obsessed with the idea of picking the perfect grape that would yield the perfect wine.

The problem, of course, is that nothing worldly is ever perfect.  The quest for physiological ripeness often has led to excess rather than equilibrium, let alone perfection.  Indeed, to my mind (and palate), the pursuit of physiological ripeness has caused more problems than it has solved.

Think back to that summer peach.  At its best, it’s not just sweet.  The skin provides a hint of astringency or tartness; the flesh is soft and sugary on the outside but firm and not as sweet close to the pit; the juice has a tangy quality that prevents it from seeming sappy.  It’s delicious precisely because it’s not monolithic.  If, however, the peach is entirely soft, with no hint of sharpness, it will taste sweet but simple.  And, of course, if it is over-ripe, it will feel mushy and taste so sweet as to become unpleasant because cloying.

A great many contemporary wines, including many expensive so-called “fine wines,” are like that overly soft peach, and some even resemble the mushy over-ripe one.  They sport high alcohol levels, have soft tannins, lack acidity (unless the winemaker has added acid, which invariably leaves the wine seeming disjointed), and taste primarily if not exclusively of sweet, ripe fruit.  Though they may be tasty, they also are one dimensional and so ultimately dull.

Winemakers who obsess over “physiological ripeness” are deathly afraid of anything that even hints at tartness.  They don’t want the grapes they use to have green seeds, so their wines usually convey nary of hint of anything vegetal.  They also don’t want the grapes to have firm skins, so their red wines often lack a tannic backbone.  And because they want the pulp of the grapes to be soft and pliable, their wines too often end up seeming jammy and unbalanced.    

I am obviously painting with a very broad brush here, as there are many superb and wondrously complex wines made all over the world today.  But given the scientific and technological advances in grape growing and winemaking of the past few decades, there surely could, and should be more.  I can only judge using my own sense of taste, but the best wines I have ever tasted all have been multi-faceted and harmonious.  Too few wines I taste today satisfy those criteria.

The quest for “physiological ripeness” began back in the 1990s when the winds of wine fashion started shifting away from elegance towards power.  It went hand in hand with the desire to make wines that would earn high grades from influential critics who expressed a preference for that fashion, and for a time it served as a corrective as well as a passion.  But fashions never stay constant, and there are many signs indicating that the winds are shifting back again.  Perhaps when that happens, vintners will return to common sense and admit that seeds, skins, and pulp have little to do with ripeness, which as everyone has known ever since Antoine Lavoisier proved it so, refers to the appropriate concentration of sugar in the fruit--no more and no less.