How Wine is Made
There are as many variations on winemaking techniques as there are wine producers in the world. However, here are some of the basic steps that a large winemaking operation would go through, from harvest to table.
1. Pick the grapes.
The type of grape that a winemaker will choose to plant in their vineyards depends on what will grow best in their soil and climate, as well as what they think will sell best on the world market.
2. The grapes are pulped.
It can be fun to stomp them, as is traditional in France, but more often a machine is used. The pulp and skin of the grapes are included when red wine is being made, but for white wine, only the juice of the grape is used. This results in a more refreshing beverage ultimately, but reduces the range of possible flavors and aromas.
3. Primary fermentation begins.
Yeast is added to the pulp or juice, and the mixture is allowed to sit for a week or two. During this process, most of the grape sugars are converted into ethanol, as well as carbon dioxide which goes into the atmosphere. Ethanol is what makes the wine alcoholic.
4. Secondary fermentation is initiated.
During this process, the wine goes into a sealed container, traditionally an oak barrel, which imparts its own characteristics to the wine. The important part of this process is that air is not allowed to mix with the wine, which results in a slower, more deliberate conversion of any remaining sugars into ethanol. According to WineDefinitions.com, each percentage point of sugar in the original grapes is converted to about half a percentage point of alcohol content during fermentation. So, the sweeter the grapes, the stronger the wine.
Malic acids, a naturally occurring acid within grapes, may also be lost to bacteria during this process, which is often desirable, since it decreases the wine's overall acidity. This is called malolactic fermentation.
The amount of time that wine stays in the barrel depends on the type and quality of the wine. Light white wines can be drunk after only a few months, whereas many red wines, especially of noble and expensive vintage, are aged for years.
5. Finally, the wine is taken out of the barrel.
The dead yeast cells are siphoned off, and the wine is bottled. It's now on its way to store shelves and your dinner table.