In 8 cup saucepan, combine water and vinegar. Peel Jerusalem artichokes and cut into 1 inch pieces; drop into saucepan as you cut them (the vinegar keeps them white). Add potatoes. Bring to boil, reduce heat to simmer; cover and cook for about 20 minutes or until vegetables can be easily pierced with fork. drain, serving cooking water. Mash vegetables until smooth (or whirl briefly in food processor), adding salt and about 1/4 cup of the cooking water (remainder can be saved for soup). Serve hot. Makes 8 servings.

Per serving: 93 calories; 2 g protein; 0.08 g fat; 21 g carbohydrates; 2 g fibre.