Wash and stem crabapples. Slice larger ones, but don't peel, core or seed.

Place 3 lbs crabapples and 3 cups water into a large stockpot and bring them to a boil over medium-high heat. Reduce the heat to low and simmer for 20-25 minutes until the fruit have completely fallen apart.

Strain through a jelly bag for 1-2 hours. Gently squeeze the bag to get the last bits of juice. You should have 4 cups of juice, but if not, use what you have in a 1:1 ratio in the jelly recipe.

Measure the crabapple juice. For every cup of juice, add 1 cup of sugar. Place the juice and sugar into a deep jelly pot and bring to a boil over high heat. Skim off the foam and watch carefully for overflows.

Cook until the jelly reaches gel stage. Test for gel stage on a plate that's been placed in the freezer or using an instant-read thermometer. Gel stage is 220 degrees at sea level, and drops by 1 degree for every 500 feet above sea level (ie. at 1000 feet it's 218 degrees F).

Crabapple jelly reaches gel stage VERY QUICKLY. Mine gelled almost as soon as it boiled, and only cooked for 1-2 minutes after boiling. Pectin levels vary in fruit, so it may take as long as 15 minutes to reach gel stage, but still it should be quick compared to other types of fruit jelly.

Once it reaches gel stage, ladel into prepared jars leaving 1/4 inch headspace. Canning is optional, and this jelly can instead be stored in the refrigerator for 3-4 weeks or freezer for up to 6 months.

To can crabapple jelly, fill the jars leaving 1/4 inch headspace and seal with 2 part canning lids. Process the jars in a water bath canner for 10 minutes (under 6000 feet elevation) or for 15 minutes above 6,000 feet.

Remove the jars to cool on a towel on the counter. After 24 hours, check seals. Store any unsealed jars in the refrigerator for immediate use.

Properly canned and sealed jars will store on at room temperature on the pantry shelf for 12-18 months without losing quality.