If you've ever come to one of my events or got stuck in a room with me where I got the chance to talk wine, you would note my affection for acidity in wine, especially when pairing it with food. The 'Acidity Rules' thing is not just my supposition; it's based on science and has repeatedly been proven true.
I've had an instructor say that acidity is the "nervous system" of wine, and he was/is right.
Acidity in wine:
Adds structure
Adds balance
Protects against microbes
Makes it possible to further age a wine
Acidity is one of the most important elements in wine. It contributes to the wine's balance, and affects everything from its flavor to its aging potential. In this post, we break down the impact acidity has on wine and why it is so important.
The Role of Acidity in Wine
Structure
A wine's structure is made up of four things:
Acidity
Sugar
Tannin
Alcohol
The two most essential elements of a wine's structure are acidity and tannin (red wine), but more so acidity. It is the backbone of wine and the central pillar of its structure. Without acidity, a wine can feel flabby and dull on the palate. The structure simply falls apart.
Balance
A wine's balance depends on all elements in its structure being in relative harmony. For example, medium+ tannins must come with medium+ acidity, and so on.
I would argue that if any part of the structure of a wine is on the high end, it needs the acidity to match it to perpetuate balance. Think about well-made sweet wines. These generally come with low alcohol, but that residual sugar has a healthy dose of acidity to support it, propelling its balance.
Have you ever had a German Spätlese or Auslese riesling? Though these are made from late and select harvested grapes with noted residual sugar, they also come with high acidity, making the wine's sweetness almost imperceptible, and balance is born. That's the magic of acidity in wine.
Protects Against Microbes
Acidity acts as an agent that prevents bacteria and slows the oxidation process of wine. When a wine is exposed to oxygen over a long period of time, it is no longer drinkable. It does have a use though. Use it as you would vinegar because that's what your over-oxidized wine will become. This is why we refrigerate wine and use impenetrable wine stoppers in hopes to keep an opened wine drinkable for at least a week.
Aging
Not only does acidity add to a wine's freshness and limit exposure to microbes and bacteria, it is also a preservative and supports a wine's aging.
Wines that start out with medium+ to high acidity can be aged longer. Tannins, too, help in the preservation and wine aging. Without heightened acidity, a wine cannot be aged and must be drunk within five years.
Over time, the wine's tannins and acidity will soften, and the wine will appear more round on the palate.
Total Acidity and the pH Scale
In truth, two scales are used to measure acidity: total acidity and the pH scale. What's tricky with understanding the pH scale is that the lower the number, the more acidic the wine. Most wines fall within a pH of 3.0 to 3.9, whereas water has a neutral pH level of 7.0. Keep this in mind when reading a wine's specifications, and the winemaker proudly speaks to the pH level of the juice contained in the bottle.
Mostly, what you need to walk away with is an understanding of just how vital acidity is to a glass of wine.
In a later post, we'll go deeper on acidity and food to support our belief of why wines with crisp acidity do so well on pairing menus.