Acid in Wine: A Brief and Profoundly Dull Tutorial

As far as I can tell, the only difference between wine and LSD is that one is legal and the other is not.  Oh, and one makes you feel horny and self confident, fun and brimming with bonhomie and the other makes your walls melt and your friends grow bird heads.

CHRIS ONEALOther than that, both contain a chemical known as ‘acid’, which in its most simple definition is a substance which reacts to a base, although in the case of Pittsburgh Pirates pitcher Dock Ellis who threw a no-hitter while tripping on blotter acid, there weren’t any bases to react to.  (In the interest of complying with the 1927 ‘equal-time rule’, Ellis was also a wino, and once got into a fight with a Riverfront Stadium security guard while wielding a half-empty bottle of something we can presume was not a 1961 Hospices de Beaune Emile Chandesais).

Acid also reacts to metals like calcium and police badges and will turn blue litmus paper—and the faces of parole officers—red.

This is fairly mundane knowledge that most seventh grade whizbangs know, and really does no justice to the critical role that acids play in the enjoyment-factor of wine.  Without a specific percentage of tartaric and malic acid as a structural component, wine becomes undrinkable.

Here’s A Science Experiment To Re-Enforce the Point, Courtesy of Little Jacob ‘Pindixter’ Janeway, 7th Grade Earth Science

Pinsy Janeway looking up Dock Ellis’s ERA

Little Pinsy says, “If life hands you lemons, make lemonade.  And then add a boatload of vodka.”  Wise beyond his years, that one.  Little Pinsy points out that if you mix sugar and water, you wind up with an insipid, cloying, flaccid beverage that only ghetto kids will drink, but if you make a very simple pH adjustment and add lemon juice, you have created a wonderfully refreshing drink that the upper strata of society can enjoy, especially when purchased from ghetto kids with curbside lemonade stands.

Urban entrepreneurship

So it is with wine.  As mentioned, the primary acids in wine grapes are tartaric and malic, with amounts that vary between varietals and depend heavily on where the vineyard is located.  As wine writers often note, ‘Warm days are needed to build up sugars and cool nights are required to preserve the acidity,’ and so they are.  As in Pinsy’s cocktail, an equilibrium of sweet and tart are key to a wine’s perceived sumptuosity.

Both acid and sugar production are natural to a grape’s growth and maturation, but as chemical processes, they’re opposites. For the most part, grapes grown in warmer climates have more sugar and less acid and those from colder regions are higher in acid and sometimes need to be sweetened artificially after crushing.  This technique, called chapatalization, is not permitted in California, but it’s fairly common in the cooler regions of  Europe, and is allowed in Oregon and New York.

Adjusting either sweetness or tartness in a wine must is elementary to winemakers, although it is essentially considered an undesirable, manipulative and unnatural step.  As can be imagined, it involves adding sugar or acid (tartaric usually, but sometimes citric or malic) around the time of primary fermentation.

Too Much Information spec sheet

On to Specifics

Vintners love loading down their spec sheets with arcane percentages and chemical symbols that most of us don’t understand. It makes them feel all sciencey, like there is something more to their profession than walking around vineyards and watching Mexican people work.  So, below their ‘winemaker notes’ (filled with descriptors we don’t understand either, like creosote, lychee, burnt tar and torrefaction, etc.), you’ll often see line items like Brix at Harvest, Acidity and pH.  Unless you have some mental level-set with which to interpret these tidbits, you probably don’t care if your sangiovese has a pH of 3.56 or 3.49 so long as it doesn’t kick the Pasta Ponza in the coglioni.

Come On, Lucky Number Seven

Alkaline = Base.         Al Kaline = Baseball

For technical reference, pH is the number of free hydrogen ions in a given solution,  where a pH of 7, measured at 77°F, was chosen by some adult version of Pinsy as a neutral kick-off point—water, in other words, has a pH of 7.  The higher the pH number, the more alkaline (not to be confused with Al Kaline, the Detroit Tiger who shone in the 1971 All-Star Game against Dock Ellis) the liquid; the lower the number, the more sour it seems.  The gradients are similar to the Richter Scale in that a solution with a pH of 3 is ten times more acidic that one with a pH of 4.

Wines typically come in at between 2.8pH and 4.2pH, with 3.5 being about ideal for reds, a bit lower for whites.

You’ll also see Total Acidity, or TA listed in a wine’s liner notes, usually given as grams per 100 mL—a calculation which is even farther out in left field than Willie Stargell was during Dock Ellis’s no-hitter—I mean, who knows how much a milliliter is?  More to the point, who cares?  Civilized alcoholics are into gallons and quarts.  Even so, both TA and pH are offered as eno-talking points because, although the result is the same, they look at wine acidity from slightly different angles.  Whereas TA measures the overall acid present in a wine, pH records the strength of that acid.  Most ‘to add or not to add’ questions regarding a wine’s acidity adjustment are made using pH values rather than TA.

Beauty shot of oenococcus oeni

Malo is a Mellow Fellow

Another word that you can toss around at seventh grade wine tastings to make yourself look smart is malolactic fermentation, sometimes abbreviated to MLF.  In nearly all red wines (exceptions being lightweights like gamay or dolcetto), and whites with pronounced levels of metallic-tasting malic acid (an exception being riesling, where malic works magic), a secondary, ‘softening’ fermentation occurs, either naturally or as a winemaker-induced inoculation. During this conversion process, malic acid is transformed into lactic acid, the stuff that’s in milk and makes it coat the tongue.  The active bacteria that allows this to happen is called oenococcus oeni, and in the plus column, it can take an overly malicky wine, often recognizable by sharp, green apple aromas and tastes, and covert these flavors into something akin to butteriness.  Both profiles are frequently found in chardonnay, and in fact, chardonnay is a varietal where malolactic fermentation is either squelched or encouraged depending on the winemaker’s preferred outcome.  Viognier, a cultivar where a certain creaminess may also be desired, is another malo candidate—the secondary fermentation adds a level of depth, weight and complexity to this already interesting grape.

That said, some vignerons claim that MLF robs a wine of its natural fruit and stylistic  character, so the decision to begin the conversion process is never taken lightly.  Equally, if unprompted malo begins to occur where it isn’t wanted, it can be stopped by the addition of sulphur.

In the end, great wine keeps all of its multi-faceted yin and yang in check and balance.  Like memorizing an endless roster of baseball statistics, the minutia of winemaking is a pain in the kiester to master, but either way, once done, you wind up with a deeper appreciation for the science behind both the swing and the swig.

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1 Response to Acid in Wine: A Brief and Profoundly Dull Tutorial

  1. Thank you for some other magnificent post. Where else could anyone get that type of information in such a perfect method of writing? I have a presentation subsequent week, and I am at the search for such information.|

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