Lab Coats, Everyone!

Here in the Wine Corner, we don’t go in much for fancy dress — you won’t find us stocking shelves or flourishing our feather dusters in monogrammed jumpsuits or sporting FK-branded baseball caps. It’s a sartorial decision consonant with our overall approach, which we think of as straightforward and commonsensical, with the emphasis on the everyday sensory pleasures wine provides, explained, as best we can, in plain language and without recourse to jargon or geekish obfuscation.  And yet…

There are moments when it seems worthwhile to give some attention to what actually makes wine what it is — or better, what makes one wine different from another — in a way that goes beyond the more obvious, macro-scale determinants provided by varietal character, vineyard site and soil type.

Illuminating how a particular wine goes about its business requires molecular-level biology and chemistry.  So slip on your lab coat, grab a beaker and join me for a little excursion into the wonderful world of pH, possibly  the most important determinant of wine quality you’ve never considered.

I’m betting you’re on familiar territory in knowing that a water molecule represents a bond of hydrogen and oxygen.  All water-based solutions have a measurable hydrogen ion content: its hydrogen potential, or pH, rated on a scale from 0-14.  A pH below 7 is considered acidic;  above that, the solution becomes increasingly alkaline. Agreeable drinking water hovers right around the balance point of 7.  Wine, mostly water, normally measures between about 3.0 and 4.0. There are several very good reasons why it’s desirable for wine to register near the lower boundary of this range than otherwise.

The first is that the yeasts responsible for healthy, sustained, thorough fermentations tend to thrive in acidic conditions, while the bacteria likely to cause disagreeable scents and flavors do not.  Since a sound fermentation is in part dependent on yeasts multiplying at such a rapid pace that they crowd out malicious competitors, a low pH environment is ideal.

Higher acidity also makes the antimicrobial effect of naturally-occurring (or added) sulfur dioxide about 10X as effective as it would otherwise be. For winemakers seeking to work with minimal (or zero) additions of SO2, this represents a real boost to their efforts.

A third advantage has to do with both appearance and taste. Low pH environments bestow both brighter, clearer colors on red wines and are adept at delivering fresh, brisk, appetizing flavors.

Finally, there’s something to be said for the interplay between wine and human anatomy, which is where the rubber truly meets the road. Since the pH of the mouth hovers between about 6.5 and 7, wine is able to provide a healthy dose of those appealing sensations we collectively refer to as refreshment.

There’s lots more to be said on the subject, particularly with reference to techniques winemakers use to reach the levels of acidity in their fruit that will realize the wine they have in mind.  But we’ll leave all that for another time … when we’ll swap out the lab coats for overalls.