The shape of the body of the wine glass, and the size of the opening, determine how the wine enters the mouth. This is because the different shapes of the wine glass body guide the wine to flow into the appropriate taste areas of the tongue (there are four different taste areas of the tongue, the tip of the tongue is the most sensitive to sweet, the back of the tongue is the most sensitive to bitter, and the inside and outside of the tongue are the most sensitive to sour and salty respectively), thus determining the final presentation of the wine's structure and flavor. Thus, while the glass does not change the essence of the wine, its shape can determine the direction, smell, quality and strength of the wine, which can affect the aroma, taste, balance and finish of the wine with surprising influence.