Acidity in Wine

Blackwood Canyon Vintners - Acidity in WineAcidity is an extremely important and often misunderstood element of wine. When we speak of acid balance, it is important for the modern consumer to understand that acid levels in wine have been steadily decreasing since the 1980’s, due in part to large American beverage corporations industrializing the wine industry and pushing the style of wine toward a lower-acid, ‘easy-drinking’, cocktail-type beverage which can be released quickly and sold to the masses. Unfortunately, nearly the entire market of modern, American-made wine is now made in this fashion (and many European wines, as well). This style might be fine for some consumers in some situations, and it is great for a winery’s bottom line, but unfortunately it has served to nearly completely eliminate the ‘Mozarts’ of wine and has replaced them with varying levels of elevator music.

When we refer to acidity in wine, we are mostly speaking of tartaric acid, which is overwhelmingly the majority source of total acidity. Tartaric acid binds with potassium to form potassium metabitartrate (cream of tartar), which can sometimes form (harmless) crystals, referred to as ‘wine diamonds’, on the cork of a bottled wine. Tartaric and other wine acids are responsible for the ‘tart’ characteristic of wine, and can sometimes be described as ‘sour’. Other acids in wine include malic, lactic, and citric, which can all add to the complexities of acidic flavors in a wine. Levels of these acids determine a wine’s pH and titratable acidity, or total acidity (TA).

The pH level is the measure of the free hydrogen ions present in the wine, and it is measured as a negative algorithm, meaning that the lower the number is, the higher the free hydrogen. More free hydrogen ions in wine increase the perception of acidity to the drinker. For example, a pH of 7.0 indicates a ‘neutral’ solution, such as water, and any number lower than 7.0 indicates an acidic solution. Prior to 1980, the University of California at Davis was warning its students that producing a wine with a pH of 3.5 or higher constituted ‘commercially unacceptable’ winemaking due to the wine’s lack of acidity. In contrast, for wine made in modern times, pH levels of 3.7 and higher are very common. Similarly, classic TA levels were typically .75 - .85 for white wines and .6 - .7 for reds, whereas wines made today can frequently be lower than .50.

Why is all this important?

The amount of acidity in a wine determines its balance and is an integral element in its overall structure. Also, an adequate level of acidity can provide protection from certain wine microbes. Acidity can play a role in determining how long a wine will age, how well it will pair with food, and in general how much the wine ‘pops’ on the palate of the drinker. A TA level below .6 and a pH level above 3.5 can tend to make a wine taste (and feel) flat, heavy, and sometimes flabby. This is subjective, of course, and some consumers prefer low-acid wines, referring to these as being ‘supple’ or ‘smooth’. In contrast, a wine that is high in acidity can taste ‘sharp’ and ‘biting’, and often-times can be confused by many consumers to have turned to vinegar. This is nearly impossible, though, since vinegar (acetic acid) is produced during the latter stages of glycolysis and requires the presence of oxygen, which is not present in a properly sealed bottle. Additionally, the presence of alcohol above 13% inhibits the development of acetobacter (the bacteria responsible for the creation of acetic acid).

So why make a wine with high acidity? There are a couple of reasons, but part of the answer to this question requires an understanding of what happens to wine as it ages. Acidity in wine will decrease over time. That being the case, if one wants a wine to have proper balance in, say, ten years, one would require the acid level to be much higher initially than if one wanted to enjoy the wine in three years or less. It is a well known phenomenon that wine improves with age when made properly, and a wine made to cellar will need a much higher acid level in its youth than a wine which is not intended to age. This is part of the reason why drinking a classically well-made wine while it is young can be a mistake, since it will tend to taste ‘sharp’. Conversely, a wine made with low acidity will ‘flatten out’ and die long before it sees its tenth birthday.

Acidity will also decrease once a wine has been decanted. To understand this, an explanation of esters is necessary. Esters are the compounds that are responsible for the majority of what is commonly referred to as ‘the nose’ or ‘the bouquet’ in wine. In general, esters have pleasant odors and are present in perfumes, flowers and fruits. There is a direct relationship between acids and esters, in that esters contain one more oxygen molecule than acids. As the phenolic compounds present in the wine ‘steal’ the available oxygen in a sealed bottle, the esters eventually lose one oxygen molecule and become acids. As a wine is decanted and released from the bottle (which is, in effect, an oxygen-deprived prison), it will be somewhat higher in acidity until some of the acids revert back into esters as they gain oxygen, thus creating bouquet. This is one of the most important reasons for decanting a good wine.

A proper amount of acidity is of paramount importance in a wine’s ability to pair with food. It gives the wine an ability to separate the flavors of a dish, as well as combine with other flavors to enhance the food. When one considers the importance of acid and food, it is helpful to think about the example of using vinegar as a salad dressing or sauce additive, or squeezing lemon on fish, or into an apple pie. The acid serves to brighten or ‘set off’ the dish in a way that could not be achieved otherwise. Acid can also ‘slice through’ certain fatty foods and cleanse the palate. These are largely the reasons wine has traditionally been a fixture at the dinner table throughout the centuries in Europe, and continues to be today. It can sometimes be more accurate to describe a well-made, properly-balanced wine as a sauce or a condiment that enhances one’s food as one sips, rather than simply a beverage.

For all of these reasons, Blackwood Canyon has maintained the classic acid balances of the 1970’s and before, due in part to our location, but also to our winemaking technique. Most of the great wine-growing regions of the world are located in cooler climates that produce a lively acidity in the grapes. The cooler growing region of Washington State, in some ways similar to Burgundy, Bordeaux, or Germany, allows for fruit that is ‘crisp’ and ‘bright’, compared to warmer regions like parts of California, Greece, Algeria, Italy, etc, where the fruit can be flat and flabby. Our traditional use of ‘lees’ aging, which works to extract more complex flavors from the fruit, also extracts higher acidity in the process. As our wines age in the bottle, as with all great, classic wines, the acidity decreases and allows the amazing length and complexity of the wine to shine through, while still providing proper balance and (after proper decanting) a tremendous bouquet.