| Acid Basics or The Basics of Acid
Acid – even the very mention of it conjures up images of burning flesh or lemon juice squirting in your eye. Acid gets a bad rap, and some people will go out of their way to avoid its puckering clutches. Does acid deserve this nasty reputation, or is it just a case of mistaken identity?
Acid is a misunderstood concept, often taken to mean sour, vinegar-like or bitter, but there are many types of wine acids as well as tannins, for which acids are often mistaken. Acid has many forms and faces, but all are as essential to red and white wine as sugar or alcohol.
There are both good acids and bad acids – the key to good acid is in the balance and the type present in the wine. The predominant wine acid is tartaric, which is the main acid in ripe grapes. Tartaric acid is what gives balance to sugars in white wines and tannins in reds.
For a wine to be successful (i.e. not taste like flat grape soda or balsamic vinegar), it needs to have a careful balance between the acid and the other components in the wine, such as tannin, sugar, alcohol, glycerin and fruit components. This is achieved by harvesting ripe grapes. If the season is cool and the grapes do not fully ripen, then the wine is often too high in acids (both tartaric and the more harsh malic acid). If the grapes are harvested in a very hot year, the opposite is true and the wine will not have sufficient acid, resulting in flat and uninteresting flavors. Not all winemakers are created equally, and timing the harvest can be a very difficult task – better winemakers will compensate in hot years with small acid additions early in the process.
The next acid to watch out for is acetic acid, which is your nasty vinegar acid. It occurs when wine is left unattended in the presence of oxygen (wine’s public enemy number one), and when these flavours dominate a wine, it isn't pretty. The nose becomes pungent with the hallmark vinegar scent, which can eventually turn into the notorious nail-polish-remover aroma – mmm tasty.
Acid in white wine is slightly different and often a little easier to identify. Acidity is necessary in whites as it is responsible for the lively and refreshing character of the wine. Without it, the wine ends up tasting flat and tired (see a cheap Australian Chardonnay, for example – anything with a bin number will do). Lactic acid is an important acid that is present in all wines, but much more noticeable in certain whites. Lactic acid is produced by a secondary microbial fermentation, which does not involve yeasts. The byproduct is known as diacetyl and has a characteristic buttery quality (see any overpriced Napa Valley Chardonnay – the Napans seem to be enamoured of the stuff).
Acid is important not only to balance wine but also food. Wines from countries such as Italy or France tend to have higher acidity than new world wines because they are intended to be served with traditional foods. These local foods are often high in fat and this helps to soften the wine and release the subtle flavors. Pairing wine and food effectively is often just a case of balancing the acids.
The final feature of our old pal acid is helping fine wines in the process of aging – without sufficient acidity wines are unable to make the long journey in bottle.
If you want to have a little fun with acid, try picking up a few of these bottles and compare the puckering power: a Muscadet, Sancerre or Vouvray from France (this is your highest acid group); a Pinot Grigio or Pinot Blanc from Italy or France (this is your medium acid group); a Chardonnay from California or Australia (this is your lowest acid group).
Try tasting these wines with cheeses which are both high and low in fat and see how it affects the taste of the wine. Put a little zing in your life! |
