Grapevine: Don’t trip over the acid, it’s crucial to wine structure

Acid is a wine term that often makes people shriek and run away.

Unfortunately, to say you don’t like acidic wines in the most literal interpretation, is impossible. Acidity is crucial for the structure and balance of a wine and without it wines would taste flat, flabby, thin and dull.

Terms such as crisp, fresh, racy, bright and mouthwatering are used to describe the acidity of a wine without actually using the word itself.

A more apt way of describing what you do or do not like in a wine as far as acidity goes is to say you don’t like wines that are too acidic, excessively mouth-watering and dry or by narrowing down, the types of acidity you do or do not like.

To start with, we will look at the principal types of acidity you will find in wines.

You will typically only find malic acid in white wines, the green apple feel often found in coolclimate whites, typically in Riesling and certain styles of Chardonnay.

You won’t notice this as much in red wines due to the process of converting the sharp/ harsh malic acid in to the softer lactic acid (malolactic fermentation).

Tartaric acid is less perceived by flavour as by feel. The mouthwatering on the sides and back of your tongue will be driven by higher relative levels of tartaric acid.

It helps to give the wine persistence and length of flavor once you have swallowed it, while malic acid will typically only hit you in the middle of the tongue.

Lastly is citric acid; a relatively self-explanatory category, this is the characteristic lemon and lime character. While not quite as prominent as the prior two acids, it packs a punch and will be observable at much lower concentrations. There are certainly other types of acid that can pop up, but these are the big three.

Your perception of acidity will depend on many factors so we will just cover a few big ones here. First and foremost is temperature. The warmer the climate, the faster sugars in the grape will rise and inversely the acids will fall, thus the same grape variety grown in a cool-climate wine will usually display higher levels of acidity than that from a warm climate.

Sugar is another touchy subject for many wine drinkers, but it is just another factor that can be good or bad depending on the context and balance of a wine. Acidity and sugar will reduce the perception of the other, so a very high acid Riesling can be tempered by leaving some residual sugar in the wine, which doesn’t necessarily make the wine taste sweet but will often add some weight, body and softer/ luscious texture. In fact, some of your favourite white wines may well have a few grams of residual sugar to balance the wine which you are not even aware of its presence.

Finally, the most vivid example is the process of malolactic fermentation whereby the harsh malic acid is converted in to the soft lactic acid. Take a crisp cool-climate Chardonnay and compare it to a big buttery, you will see the marked difference this process has on the wine.

Given the familiarity with Riesling as being a grape high in acid, it is worth tracking down the Dinny Goonan Riesling ($25). You will notice classic Riesling characters to start, but then notice the softening effect of some malolactic fermentation as the wine becomes much softer and rounder towards the back of the palate. Only a small portion of the wine goes through malo, but the change to the texture and structure is marked.