1. In a bowl, mix nectarine slices with 3 tablespoons lemon juice. Whirl, a portion at a time, in a blender or food processor until very smooth. Return purée to bowl.
2. Add Gewürztraminer, sugar to taste, and more lemon juice if desired. Nest bowl in ice water and stir often until mixture is cold, 5 to 10 minutes.
3. Pour chilled purée into an ice cream maker (1-qt. or larger capacity). Freeze according to manufacturer's directions until sorbet is firm enough to scoop, dasher is hard to turn, or machine stops.
4. Serve, or freeze airtight (see below)
Firming and Storing Ice Cream:
To get frozen desserts hard enough to scoop onto a cone, or to store them, transfer when frozen to an airtight container and put in the freezer at least 3 hours or up to 1 week.
If freezing with ice and salt, leave the frozen dessert in ice and salt up to 3 hours.
For best flavor and texture, serve frozen desserts within a week. On longer standing, icy crystals develop.
Nutritional analysis per 1/2 cup.