Acidic Wine Meaning


Acidic Wine & The Tuscan Table.

What does the term acidic wine mean, and who wants to drink a wine like lemon juice? Here’s a three minute read with the answers.

Most of us enjoy the sensation of freshness that some wines give. This is due to a number of factors, but acidity is the main player. This applies to many other drinks too. I’ve been brought up on the Italian table, and this often means acidic wines. This is particularly the case in the Tuscany region. I guess it’s a matter of habit, but I find it hard to enjoy wines where the acidic component is subdued.

Chart showing the meaning of acidic wine

Perceived acidity

Perhaps it would be more correct to say these are wines where high sugar levels mask the acidity, thus altering our perception. This because sugar doesn’t alter the concentration of acid, it just makes our taste buds less aware of it. So for my tastes, these wines are flat and lacking in freshness. In a word “unbalanced.” The other elements that mask acidity are tannins which produce that dry puckering sensation, and alcohol.

Balanced unbalanced

A balanced wine is one where acidity, alcohol, residual sugars and tannins interact in perfect way. An unbalanced wine is obviously the opposite. For example too much acidity will result in a sour taste, too little will make the wine sweet. Too much tannin will confer a bitter, dry sensation. Too much alcohol which sounds like fun, overpowers all the other flavors. High alcohol levels can also be a trick to make a poor wine seem better.

What is an acid?

I’m not a chemist, so here’s a simple definition which even I can understand. An acid is a chemical substance with pH of less than 7.

So what is pH

pH is a scale used to specify how acidic or basic a water-based solution is.  The scale goes from 0 to 14. Acidic solutions have a lower pH, while basic solutions have a higher pH. At room temperature (25°C or 77°F), pure water is neutral being neither acidic or basic. The pH is 7. Read more on Wikepedia.

How the acid in wine is measured (pH)

The acids in wine are present in both grapes and the final product, and they affect the color, balance and taste. They also condition the growth of yeast during fermentation, and ultimately protect the wine from bacteria. So obviously the pH is a very important part of wine making. There is however a range, and too high or too low would makes things impossible.

The acidity in wine has two measurements which are; total and strength. The measurement we laymen are familiar with (and the subject of this article) is the pH. The pH refers to the strength. Most wines have a pH between 2.9 and 3.9, and the lower the pH the higher the acidity. Contrary to what one would believe, there is no direct connection between total acidity and pH.

The acidity of Tuscan Wine

My Tuscany wine tours take us the Chianti region and of course to the home of Chianti and Super Tuscan wines. The average pH of these wines is around 3.5 with zero residual sugar. This means you can expect dry wines with a certain zing and freshness.

The Primary Acids

There are are a quite a number of acids involved in winemaking, and they all have an influence on the final product. Some are positive and some are negative. The primary acids are Tartaric, Malic and Lactic and Acetic. Most of these acids are fixed acids, with the exception of Acetic acid. This is the acid we mostly find in vinegar. Acetic acid is volatile and can contribute to the wine fault known as volatile acidity. Sometimes, additional acids, such as citric, ascorbic, sorbic and sulfurous acids, are used in winemaking.

Tartaric acid

Tartaric acid in wine making is the most important due to the role it plays in maintaining chemical stability and color. It’s also very important for the taste of the finished product. Tartaric acid is a rare in most plants, but the grape vine contains significant amounts. The concentration varies depending on grape variety and the soil content of the vineyard. Sometimes the Tartaric acids can crystallize and may appear like broken glass. They are harmless but winemakers will put the wine through cold stabilization, which causes the Tartrates to precipitate out of the wine.

Malic acid

Malic acid is another organic acid found in wine grapes. It can be found in almost all fruits, and is often associated to green apples. This is also the flavor it tends to give to a wine.

Malic acid in the vine is involved in several processes which are essential for its sustainability. Its concentration varies depending on the grape variety and the time of season. It’s at its peak just before veraison. Then as the season progresses, it’s metabolized with the process of respiration of the vine, and will be very low by harvest time. The respiratory loss of malic acid is more pronounced in warmer climates. When all the Malic acid is used up in the grape, it is considered “over-ripe.”If this happens the winemaker must compensate by adding acid at the winery. This process is known as acidification.

In the case of Tuscan wines such as Chianti and Brunello, the grapes are harvested long before they are over ripe. Therefore the residual Malic acid will be further reduced during through a process known as malolactic fermentation. In this process, bacteria convert the stronger Malic acid into the softer lactic acid. Malolactic fermentation will increase the pH (less acidic), and consequently give a different sensation in the mouth.

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