My friend, Jon Lusby, taught me how to make fruit tonics one summer. He has now created Fermentation Creation and is selling fermentation kits at www.fermentationcreation.com.
Take the berries that were left from the mulberry punch recipe. Place them in the bottom of a clean half-gallon jar (Jon's kit work great!) Add ½ cup of sugar, ½ cup of whey (made from raw milk or good yogurt), and water to fill the jar almost to the top. Put on a lid with an airlock. Let sit 24 hours.
Strain the fruit out and bottle the liquid in Grolsch bottles. I had my first tonic after two days and it was delicious. After two weeks or so. It develops a slight effervescence. Again, it is delicious and nutritious.