It is said that a wine without acidity is a wine without life. All wines are acidic by nature, as they come from an acidic raw material. Likewise, the acidity is essential in wine, both from the point of view of its conservation, as well as for the smell and taste.
Small explanation about the different types of acidity: Throughout the maturation, the grape contains most of the acids involved in the vegetative cycles and other reactions that the plant performs. Thus, tartaric and malic acids represent more than 90% of all the acids in the grape, being synthesized in the leaves and especially in the same clusters. Despite their chemical similarity, these acids are formed by very different routes and their evolution is not the same throughout the maturation cycle.
Types of acid in wine:
- Tartaric acid
- Malic acid
- Citric acid
- Succinic acid
- Lactic acid
Let’s see below in a simple way how it is presented and what each type of acid contributes to the wine:
1. Tartaric acid
It communicates a certain hardness when drinking if it is very abundant. If during the winemaking process the temperatures are low, it can cause the formation of completely harmless potassium and calcium salt crystals, which can be found in the tanks of certain bottles and which indicate that the wine has not received a correct stabilization.
2. Malic acid
It is found in greater quantity in the must and not in the wine. It is important for the conservation and life of some wines. It disappears due to the action of lactic bacteria.
3. Citric acid
This acid slowly disappears when fermented by bacteria. It is not very abundant in the grape.
4. Succinic acid
During fermentation is when it makes an appearance. It does not evolve with wine and constitutes one of the elements that provide the characteristic flavor of fermented beverages.
5. Lactic acid
Lactic acid comes from the grape’s malic acid, it is much milder than this, and it is produced during fermentation by the action of lactic acid bacteria, in the so-called malolactic fermentation (after alcoholic fermentation). Lactic acid is much more abundant in reds than in whites, since the latter usually do not undergo malolactic.
These acids are part of the fixed acidity of wines, but there is another acid, acetic acid, which is responsible for volatile acidity. Natural product of fermentation, it increases slightly with malolactic fermentation and is easily detected by the nasal route.
How is acidity related with wine quality?
As we have seen a quality wine must have its acidity, but to obtain a balanced wine it is necessary to measure certain parameters in the acids present in the wine.
The acidic parameters that influence the quality of a wine are: pH, total acidity, volatile acidity and malic acid.
Ph is mainly involved in the acid sensation of the wine, but it also affects the color and preservation of the wine. The normal values in the wines range between 3.10 and 3.90.
The graph shows the acidity of the wine compared to other food liquids. If anyone interprets with this scale that a wine with 3.1 acidity is a sweet wine, error! It simply compares with other nearby acidity products.
The total acidity reflects the sum of all the acids in the wine. It is expressed in tartaric acid, and the normal values range between 4.50 and 6.00 grams per liter.
Volatile acidity calculates the acetic acid in a wine. Normal values range from 0.30 to 0.60 g / l. When a wine is chopped (due to alteration or excessive aging in oak barrels) it presents a volatile acidity above 1 g / l and aromas reminiscent of vinegar and varnish. In these cases, the expression “It is volatile” is widely used.
A curious note is that some well-known wines with prices starting at € 100 a bottle, have volatile contents above 1 g / l. In fact it is said that it is not a good XXX if it does not have more than 1 g / l.
Malic acid gives us an acid, fresh sensation. Red wines, which have undergone malolactic fermentation to eliminate this malic acid, have less acidity of this type compared to white and rosé.
Other acids present in wine also provide aromas when they are in sufficient quantities to exceed the perception threshold. For example, isobutyric acid transmits sweet, fruit and cheese aromas.