A red wine's smoothness is determined by a number of factors, including the type of grape used, the wine's aging process, and the tannin levels. The type of grape is the most important factor in determining a red wine's smoothness. Some grapes, such as Merlot and Cabernet Sauvignon, are naturally more smooth and mellow than others. The wine's aging process can also impact its smoothness. Wines that are aged in oak barrels tend to be smoother than those that are not. Finally, tannin levels can also affect a red wine's smoothness. Wines with lower tannin levels are usually smoother than those with higher tannin levels. Science of Red Wine The science of red wine is a fascinating subject. The color of red wine is determined by the pigment in the skin of the grape. The longer the grape skins are in contact with the juice, the more pigment is extracted and the deeper the color of the exclusive wine . The tannins in the grape skins also contribute to the flavor and astrin...