Soup is lightly laced with sherry for the elegant fragrance that it adds. Since much of the sought-after subtle aroma of sherry dissipates into the air within minutes after the fortified wine comes in contact with the hot soup, it is essential not to add it too soon. An even greater cooking transgression than adding the sherry too early is to compensate for the expected fragrance loss by using more than a teaspoon of sherry per cup of soup. Although the delicate fragrance of the sherry will escape into the air, the soup will be overpowered by the not-so-delicate sherry taste, which does not dissipate into the air so readily.
** Asian Recipes