Crabapple jelly is prized for its rich color and intense flavor. When it's made from bright-red crabapples, the jelly is a deep rose instead of the traditional amber color of apple jelly. Picking the crabapples requires a bit more work that harvesting full-size apples, but preparation is quicker, as the miniature apples are cooked whole and require no coring. For many home gardeners, the flavor and appearance of crabapple jelly outweighs the added effort required for harvesting.
Wash the crabapples in cold water to remove pesticides and insect residue. Remove the blossom end and stems. Discard any leaves or other plant debris.
Place the crabapples in a cooking pan, and cover them with water. Generally, one cup of water is needed per cup of crabapples.
Bring the crabapples and water to a boil. Reduce heat and simmer until crabapples are soft, in approximately 20 to 25 minutes. Monitor the apples closely, stirring occasionally to prevent scorching. Overcooking destroys the pectin in the apples and prevents them from making good jelly.
Place the cooked crabapples in a double layer of damp cheesecloth or a damp jelly bag. Suspend the bag over a bowl to allow juice to drip from the bag. Do not squeeze the bag, as this causes cloudy jelly. Allow it to sit until all juice has dripped from the bag. This may take an hour or more.
Measure the juice collected from the crabapples. Add equal amounts of sugar to the apple juice to make jelly.
Bring the mixture to a rapid boil, then reduce to a slow boil. Boil until the temperature reaches 8° Fahrenheit above the boiling point in your area. Average boiling point is 220° Fahrenheit, but does vary with altitude.
Skim off the foam at the top of the jelly with a slotted spoon or soup skimmer. Pour jelly into sterilized jelly jars, leaving ¼ empty for headroom. Seal with the appropriate lids.
Process in a hot water bath for five to 15 minutes, depending on your altitude. According to the National Center for Home Food preservation, areas with altitudes of less than 1,000 feet require five minutes, those between 1,001 feet and 6,000 feet require 10 minutes, while those above 6,000 feet require 15 minutes for half-pint jars of jelly.
Remove the jars from the hot water bath with tongs. Place on a folded towel or soft cloth in a draft-free area to cool.
Check that all jars are sealed once they have cooled. An indented lid that does not spring back to the touch indicates a sealed jar.
Store the jars of jelly in a cool, dry area out of direct sunlight for winter use. Jelly in unsealed jars may be eaten immediately or stored in the refrigerator.