Making wine : vinification

Vinification is the process of turning grapes into wine. Grapes naturally possess everything that is needed to make wine and in natural wine, ripe organic grapes are the only ingredient.

In conventional winemaking large numbers of additives are used to speed up and control this process, and to ensure a safe, predictable product.


Central to the process is fermentation, the conversion of the grape's natural sugars into alcohol and carbon dioxide.

Vinification can be roughly divided into what happens before, during, and after fermentation. Below is a brief sketch of the most important points.

Before fermentation

  • Harvesting

    Best done by hand, commonly done by machine.

  • Crushing/pressing

    The skin of the grapes is broken to release the sugary juices, exposing them to the yeasts for fermentation.

more on pre-fermentation


There are generally two types of fermentation in wine, which may or may not take place simultaneously.

  • Primary fermentation

    The conversion of the grape's stored sugars into alchohol and carbon dioxide. Carried out by yeasts.

  • Malolactic fermentation

    The conversion of malic acid into lactic acid and carbon dioxide. This changes the taste of the wine but does not affect its alcohol content.

more on fermentation

After fermentation

  • Maturing

    Wines may be left to mature in barrels for as much as three years before being bottled for release.

  • Clarification

    Conventional wines will be cleaned up in a variety of ways, and sterile filtered before bottling.

  • Bottling

    It is almost universal practice to add sulphur dioxide at this point, to prevent or retard changes in the bottle.

Some winemakers will further mature their wines in bottle before they are sold.

more on post-fermentation