wine degustations are in the process of cleaning out or removing any residual sugar or tannin left in the wine after it has been bottled. They remove these elements before the wine can be marketed and sold.
Because most red wines are processed before they are bottled, the amount of these chemicals added to the liquid during processing is relatively minimal, especially compared to the amount of sugar added to white wines that undergo multiple processing steps.
Red wines can undergo filtration as well, which removes many of these chemicals, as well as a few more, and this process can also remove some of the higher alcohol content of red wines, resulting in lighter wines for drinking.
While all wine Degustation’s are less than desirable for wine drinkers, some varieties have higher concentrations of these chemicals as well as other additives. Tuscany, for example, is known for its heavy-handed winemaking culture and a culture of making wines that are almost exclusively for consumption within the Tuscany region. While this is fine for consumers, who can afford this kind of wine, it does mean that many of these wines may lack in overall quality.
In many cases, they are wines that have undergone too much processing to be acceptable. The wine narrative that is told about Tuscany tends to lean toward dry reds or whites, which are often acidic and heavily tannic, rather than the sweet and delicate wines that Tuscany is so famous for producing.
There are a few winemaking regions that do not practice the extreme processing and filtration typical of Tuscany. In parts of Argentina, for instance, there is no intensive wine degustation practice. Instead, this type of wine is made from grape varieties that have high levels of natural sugars and tannins, rather than one of the extreme process methods common to Tuscany.