Recipe(tried): Orange Marmalade

I used this one for orange marmalade. I don't see why you can't use tangelos. Should be fine. I did have trouble with it setting up, as can be a problem with marmalade. It was still good.

Orange Marmalade

4 medium Florida Oranges
1 medium lemon
1 1/2 cups water
1/8 teaspoon baking soda
5 cups sugar
1/2 of a 6-ounce package liquid fruit pectin (1 foil pouch)*

Score the peels of the oranges and lemon into 4 lengthwise sections. Remove peels from fruits; scrape off white portions. Cut peels into very thin strips. In a saucepan combine peels, water, and baking soda. Bring to boiling; reduce heat. Cover and simmer for 20 minutes. Do not drain.

Remove membranes from the peeled oranges and lemon. Section fruits over a bowl to catch juices. Discard seeds. Add fruits and reserved juices to peel mixture. Return to boiling; reduce heat. Cover and simmer for 10 minutes. Measure 3 cups.

In an 8- or 10-quart kettle combine the 3 cups fruit mixture and sugar. Bring to a full rolling boil. Quickly stir in pectin; return to a full boil. Boil and stir, uncovered, for 1 minute. Remove from heat; skim off foam. Ladle at once into hot, sterilized half-pint jars, leaving a 1/4" headspace. Adjust lids. Process in a boiling-water canner for 15 minutes. (Marmalade may take up to 2 weeks to set.)

Makes about 6 half-pints.