Why is wine sparkling?

The wine can be fizzy due to the presence of carbon dioxide. There are several ways this can happen:

1. Secondary Fermentation: Secondary fermentation occurs when the wine is bottled before fermentation has completely finished. Fermentation will continue inside the bottle, producing carbon dioxide which will dissolve in the wine. This is the traditional method used to make sparkling wines such as Champagne.

2. Carbon dioxide injection: in this case, carbon dioxide is injected directly into the wine to produce bubbles.

3. Controlled fermentation: In this method, the wine is fermented in sealed containers, such as autoclaves, where the pressure of the carbon dioxide produced during fermentation is maintained inside the container. This method is used to produce low-cost sparkling wines.

In general, sparkling wine can be lighter and more refreshing than still wines. However, the degree of fizziness depends on the production method and the type of wine.