WINE ACADEMY

In this issue’s column, we dive deep into a winemaking technique known as carbonic maceration. Plus, test your wine knowledge with our quiz.

WHAT IS CARBONIC MACERATION?

Carbonic maceration (or cab mac) is a form of whole-bunch fermentation applied primarily to light- or medium-bodied red wines to make them fruitier and to soften their tannins. If you’ve ever drunk gamay from France’s Beaujolais region, then you’re probably already aware – consciously or not – of what this technique does to a wine.

Unlike regular fermentation, where yeast converts grape juice into alcohol, fermentation with carbonic maceration occurs intracellularly (inside the grape). In this method, whole bunches of grapes are added to a bin or vat, along with carbon dioxide, and the lot is tightly sealed. Deprived of oxygen, the berries begin to ferment from the inside, using the available CO2 to break down sugars and malic acid and produce alcohol. Once the alcohol reaches two per cent, the berries burst and release their juice. A normal yeast fermentation then occurs, finishing the job.

Winemakers may also opt for a semi-carbonic fermentation. In this method, clusters of grapes are added to a bin or vat without additional carbon dioxide. The berries at the bottom, crushed by the weight of those above them, undergo a yeast fermentation, while the berries in the middle and at the top undergo an intracellular fermentation.

In both methods, the resulting wines are bright and juicy with low tannins and acidity, and aromas and flavours such as strawberry, banana and bubble gum. The effects will be more pronounced in wines that have undergone 100 per cent carbonic maceration over those that have undergone partial carbonic maceration.