Last week I posted an infographic on how Champagne is made. Still (non-sparkling) wine is much simpler. Here are the basic steps and some of the issues that arise at each point in the process.
Remember the basic formula for fermentation is:
sugar + yeast à alcohol + carbon dioxide
During fermentation the carbon dioxide is released. (If fermentation takes place in a sealed tank where the carbon dioxide cannot escape, the wine will become sparkling.) You'll notice that red and white wines follow a slightly different path for the pressing and fermentation steps. This is because the juice of both red and white grapes is white. The red grape juice is fermented in contact with the skins to give it flavor and color.
The process is simple. However, there are decisions to make and problems that can arise at each step. Here are a few of the issues involved…
Harvest and crushing: If the grapes were not harvested at the right time, the acid/sugar balance may not be ideal, in which case acid or sugar must be added to the juice (unless doing this is prohibited by the wine laws of the region). Another consideration is how the grapes will be harvested: by hand or by machine. Hand harvesting (or at least hand sorting) is generally used for higher quality wines, because it is better for removing leaves or stems and any bruised fruit.
Fermentation: I was fascinated to learn that many winemakers do not add yeast to the juice to initiate fermentation. The fermentation can begin spontaneously due to the yeasts already present in the air and/or on the grapes. Relying on wild yeasts can be risky though, because different yeast strains behave differently and produce different flavors in the wine – some that are undesirable. (Check out this article on brettanomyces yeast.) Cultivated yeasts are a safer bet.
Maturation and bottling: There are several decisions to be made here, including how long to age the wine, whether to do it in inert vessels (like stainless steel or concrete) or in oak, and what kind of oak. Most producers release their wines for sale shortly after bottling, but others hold them back to let them age in the bottle before release.
I’ve listed just a few of the issues and decisions to be made at each point in the winemaking process. There are lots more, and each one can have a significant impact on the quality of the resulting wine. But whether it’s a $5 bottle or a $500 bottle, the same basic steps apply.