As an expert sommelier and brewer, I can confidently say that Cabernet Sauvignon is generally considered to be drier than Merlot. This is primarily due to the higher tannin content found in Cabernet Sauvignon wines compared to Merlot wines. Tannins are natural compounds found in grape skins, seeds, and stems that contribute to the overall structure and mouthfeel of a wine.
Tannins are responsible for the drying sensation you may feel in your mouth when drinking certain red wines. They bind to proteins and create a sense of astringency or dryness. Cabernet Sauvignon grapes tend to have thicker, more robust skins which contain higher levels of tannins. These tannins can impart a more pronounced drying sensation in the mouth when compared to Merlot, which generally has softer and smoother tannins.
However, it's important to note that the sensation of dryness can also be influenced by other factors such as residual sugar and acidity. While Cabernet Sauvignon is generally considered drier than Merlot, there can be variations depending on the specific winemaking techniques and the ripeness of the grapes used.
Personal experiences and situations can also play a role in how we perceive the dryness of a wine. For example, someone who is accustomed to drinking sweeter wines may find both Cabernet Sauvignon and Merlot to be relatively dry, while someone who regularly enjoys bold, tannic reds may not find Cabernet Sauvignon to be particularly dry.
Cabernet Sauvignon generally has more tannins than Merlot, which can contribute to a perceived dryness in the wine. However, it's important to consider other factors such as residual sugar and acidity, as well as personal preferences and experiences when evaluating the dryness of a wine.