1. Bring the agar and apple juice to a boil over medium heat, stirring often.
2. Reduce heat and simmer 5 minutes, or until the agar is dissolved.
3. Add remaining ingredients and bring to a boil over medium heat, stirring often.
4. Reduce heat and simmer another 5 minutes, stirring often.
5. Test for firmness (agar's thickening effect varies according to its fineness) by putting a large metal spoon with a small amount of jam in the freezer for a couple of minutes until chilled. If the jam is the right thickness, your recipe is done. If it’s too watery, stir in more agar, simmer another 5-10 minutes, and test again. If it’s too thick, stir in some fruit juice or water and test again immediately.