Crab apples can be substituted for apples in any jelly or preserve recipe. Martha Stewart, Yankee Magazine and Kraft feature simple recipes for making crab apple preserves.
To make crab apple preserves, wash and quarter 4 pounds crab apples. Add 6 cups water, and bring to a boil. Reduce the heat, and simmer from 45 to 60 minutes until the apples are very soft. Remove from the heat, and pour through two layers of damp cheesecloth layers in a fine mesh strainer. Gather the cheesecloth up so that it can be tied into a bundle, and suspend it from a wooden spoon handle set across a bowl, allowing the contents to drain into the bowl for an hour, yielding about 4 cups of juice.
Bring the juice to a simmer over medium heat. Cook for 10 minutes, skimming off foam, and add 3 cups sugar while stirring to dissolve it. Using a candy thermometer, cook until the temperature reaches 220 degrees Fahrenheit, continuing to skim off foam. Pour into sterilized jars, cool, and keep refrigerated for up to 6 months.
To preserve without refrigeration, pour jelly into dry but hot sterilized jars to within 1/2 inch of the top and cover with 1/8 inch of paraffin. If sealing with 2-piece metal lids, fill jars to within 1/8 inch of top. Once sealed, the jars can be stored in a cool, dry, dark location.