Orange-Grapefruit Marmalade - cooking recipe

Ingredients

3 large grapefruits
1 orange
1 lime
1 1/2 cups water
1/4 teaspoon baking soda
5 cups sugar
3 ounces liquid fruit pectin, such as Certo

Preparation

Remove peels from fruit and scrape off excess pith. Cut peels into fine strips.
In saucepan, combine peels, baking soda and 1 1/2 cups water. Bring to boiling, cover and simmer 20 minutes.
Meanwhile, remove white membrane from fruit and section, working over bowl to catch juices. Discard seeds.
In 8-10 quart Dutch oven, combine sections, juice and undrained peel. Cover and simmer 10 minutes.
Measure 3 cups cooked fruit mixture; add sugar and mix well.
Bring to full rolling boil and boil, uncovered, 1 minute.
Remove from heat, stir in liquid pectin and skim off foam with metal spoon. Stir and skim for 10 minutes.
Pour into hot, sterilized jars and seal.