Peel the pears, then quarter them lengthwise and remove the core.
Cut into large chunks and add them along with the water to a large sauce pan. Bring to a simmer over moderate heat; cook until tender, about 10 minutes.
Let the pears cool some then transfer them to a food processor and puree until smooth.
Add the sugar, lemon juice and brandy and puree until well-combined and the sugar completely dissolved.
Transfer to a bowl and refrigerate until well-chilled.Freeze the puree in an ice cream maker according to manufacturers directions. The alcohol will keep the mixture from completely freezing hard. Scrape the mixture into a shallow bowl or tray. Cover and freeze at least 30 minutes, preferably overnight.To serve: Scoop the sorbet into stemmed glasses. Top each portion with spumante or sparkling wine to taste.
