In a medium saucepan, combine pears, Riesling, and ginger. Cover and bring to a boil over high heat, then reduce to very low heat and cook, covered, for 20 minutes. Carefully transfer pears, wine, and ginger to blender and add sugar. Cover very tightly and purée until smooth, about 30 seconds. Pour through a strainer into an airtight container and stir in lemon juice and salt to taste. Cover and refrigerate until very cold, about 4 hours.
Transfer to an ice cream maker and churn according to manufacturer’s instructions. Transfer ice cream to airtight container and chill in freezer for at least 4 to 5 hours before serving.
Recipe adapted from seriouseats.com