Last time, the topic of residual sugar was discussed. Simply put, residual sugar (RS) is a measure of the sugar (typically in grams per liter) that remains in wine after fermentation.
During an uninterrupted fermentation, the yeast will continue to convert sugar to alcohol until nearly all the sugar is gone or the alcohol level reaches the point that the yeast can no longer live. But, if a wine maker decides to interrupt the fermentation, for example by lowering the temperature to the point where fermentation stops, they end up with wines having higher residual sugar. That's one way to get a wine with higher residual sugar that tastes sweet.
In the case of sweet dessert wines, the grapes are either allowed to ripen to the point where they have very high sugar levels, dried to create a high sugar to water ratio (raisins) or, in the case of Ice Wine, the grapes are squeezed while frozen so the water does not get extracted and only a highly concentrated sugar solution results. In all these cases, fermentation starts with very high sugar levels so that upon completion of fermentation, there is a high amount of residual sugar.
Another way that wines can seem sweet has little to do with residual sugar. Wines such as Gewürztraminer and Chenin Blanc are typically thought of as sweet wines. But whereas a dry (very low RS) Cabernet Sauvignon or Zinfandel will have 0.5 to 1.0 grams per liter (g/L) of residual sugar, a Gewürztraminer can have as little as 1.5 g/L RS and a Chenin Blanc may have around 3.0 g/L RS. To put this in perspective, a soda pop will typically have around 100 g/L RS! So, yes, a Chenin Blanc may have twice the RS of a Cabernet, but it's tiny in comparison to a really sweet drink. So why are these wines often considered sweet? Typically, it's because these wines have big, bright, bold fruit flavors and aromas that we associate with sweetness such as melon, apple, honey, rose, pineapple and grapefruit. Our nose 'fools' us into believing that the wine is sweet when it really doesn't have a significant sugar content.
On the other end of the spectrum are wines such as a sweet Riesling. These can have RS levels in the 40 g/L range. This is definitely sweeter. One of the reasons that this sweetness is kept in-balance is by the high acidity of these grapes. You've probably experienced this with lemonade and sodas such as colas which are very high in sugar (> 100 g/L RS) but also have very high acidity. The characteristics of sweetness and acidity balance each other out for a more enjoyable drink.
Another common wine that tends to be sweeter is White Zinfandel. It can have RS levels of 20-40 g/L. Hence, it makes a great entry-level wine or just a sweet refreshing wine.
And, while we often think only of white wines and rosés as being the ones that can be sweet, even red wines can be a bit on the sweet side. Examples include common red wine blends found in grocery stores with brand names such as Apothic Red, Menage a Trois, Stella Rossa, Yellow Tail and Barefoot. Even the very popular Meiomi Pinot Noir has 7 g/L of residual sugar. Now you know why these brands are so popular!
As always, what's most important is that you drink what you like. And, if your taste buds steer you in the direction of sweetness, there are plenty of wines to explore and enjoy. Cheers!