These grapes produce wines that are sweet, dessert- styled wines and develop richer, riper flavors. They are picked after the normal harvesting dates, into October and sometimes November, developing higher concentrations of sugar. In many instances, some grapes may begin to shrivel on the vine. These sugars are concentrated even more, producing more viscous, intensely sweet, wine with aromas of raisins and dried fruit.
If these grapes are left on the vine even longer, into December, to the point where they can freeze, Icewine is produced. Icewine is made from frozen grapes, pressed so that the ice is separated from the sugars. This low-alcohol wine is both intensley sweet and tart, due to extremely high acidity. Originated in Germany and Austria, then and still called Eiswein, has become more popular in New World areas, like the U.S. and Canada. Riesling, Cabernet Franc, and are examples of Icewine.
This is science at it’s best !!