Bring pear juice, lemon juice and calcium water to a boil in a jam pot.
Mix dry pomonas pectin into the sugar and evenly distribute to prevent clumping.
Pour the sugar/pectin mixture into the boiling juice.
Boil hard for 2-3 minutes, stirring constantly, then remove from heat.
Pour into prepared jars, leaving 1/4 inch headspace.
Store in the refrigerator for immediate use, or process in a water bath canner for 5 minutes.
Remove from the canner and allow the jars to cool on the counter before checking seals and storing.
Notes
To Make Pear Juice ~ If starting with whole pears, first process into pear juice with a juicer or press. Alternatively, use the method described in the Ball Book of Home Preserving. For every cup of finished juice needed, add 1 cup water and about 14 ounces chopped pears (roughly 2 medium-large) to a saucepan. Don't remove the peels and cores, those have pectin and are great for pear jelly. (For this recipe, you'll need 3.5 pounds pears or about 8-9 medium fruits.) Bring the whole pot to a boil and simmer for about 30 minutes, until the pears are just starting to fall apart. Don't stir or you'll make pear sauce.Pour everything into a jelly bag or a cheesecloth-lined colander and allow it to strain for at least 2 hours (or overnight). Then proceed with the pear jelly recipe.Pomona's Pectin ~ This pectin comes in two parts, a dry powdered pectin, and calcium which you dissolve in water. The calcium activates the pectin even with low sugar, which means you don't have to add nearly as much sugar as you would with Sure-Jell. Follow the instructions of the package to make calcium water, and then add it with the juice. MIx the powdered pectin with the sugar so that it's evenly distributed and doesn't clump.For Sure-Jell ~ If using sure jelly, the recipe will not work with lower amounts of sugar. For sure jelly pear jelly, add 5 1/2 cups sugar to every 4 cups of pear juice.