Every kindergartner enthusiastically learns the contrarian counterpart of a sweet piece of candy is a sour, lip puckering lemon. And a handful of dry, unbuttered popcorn can be relieved with a refreshing glass of water. Those lessons tend to stick with us throughout life – sweet is the opposite of sour and dry is the opposite of wet.
But the wine world frequently has a way of challenging seemingly simple, incontrovertible facts such as this. To those self-professed oenophiles, sweet and dry are polar opposites. Now, despite the head scratching nature of that outlook, there is actually a good reason sweet wines and dry wines are reasonably juxtaposed.
Generally speaking, wine production starts with harvesting, crushing and pressing the grapes. Then the resulting juice is fermented and sediments are removed. Finally, the wine is aged and bottled for sale. It is during the fermentation segment of this process that a wine’s sweetness level is determined. The winemaker controls the amount of sweetness to create the desired style of wine.
Fermentation begins when yeast is added to the freshly-pressed, sugar-filled grape juice. This initiates a chemical reaction whereby the yeast cells consume the sugar particles to produce alcohol and the byproduct, carbon dioxide. The yeast will continue to consume the sugar until the wine is dry. (This means there is no longer any sugar left for the yeast to consume.) So, prior to fermentation, the juice is very sweet with no alcohol content. After fermentation, the juice is dry (not sweet) with a specified alcohol content.
There is a reason that not all wines end up dry. It’s because the winemaker halts the fermentation process at some point before the yeast can convert all the sugar. This leaves some level of sugar and, therefore, sweetness in the wine. Knowing precisely when to stop fermentation is the calculated task left up to the expertise of the winemaker.
The most common and effective way to stop the conversion is by adding sulfur to the wine. Sulfur does not affect the wine’s taste and it kills the yeast cells so fermentation cannot accidentally reinitiate later on in the bottle. Another way fermentation ends is when the wine reaches a certain alcohol content. Beyond approximately 14% alcohol, the yeast cannot survive and fermentation stops, leaving residual sugar in the wine. So, regardless of your taste preference, controlling fermentation allows for many styles of wine that are sure to please a wide range of palates.
If sour wine does not sound very appealing, you can be glad that the opposite of sweet isn’t sour, it’s dry.