Wash pears and remove the blossom and stem ends, but do not core or peel them
Cut pears into quarters and place in a large, deep stainless steel pot.
Add enough cold water to cover the fruit
Bring to a boil over high heat, stirring occasionally, then reduce heat, cover and boil gently just until pears are softened, about 30 minutes, occasionally mashing with a potato masher
Transfer to a dampened jelly bag set over a deep bowl, or into a sieve lined with several layers of dampened cheesecloth.
Allow to drip at least 2 hours.
Don't press or squeeze the fruit, as this will cloud the jelly.
You should end up with 5 cups of pear juice.
Combine the collected pear juice and sugar into a large, deep, stainless steel pot.
Bring to a full rolling boil over high heat
Stir in liquid pectin and continue to boil hard, stirring constantly, for one minute
Skim off foam and transfer to hot sterilized jars
Wipe jar rims and apply lids and screw bands
Process in a boiling water canner for 10 minutes
Remove from canner and allow to cool before ensuring jars are sealed and storing.
Notes
Depending on the size of your pears, you will end up with 4 to 6 half pint (8 oz) jars of jelly.Prep time includes two hours of passive time while the juice is extracting.If you don't end up with the full five cups of juice, pour boiling water over the fruit in the jelly bag or sieve to make up the difference.You can tell if your jars are sealed by pressing the center of the lid with your finger. If it springs back, the jar is not sealed. Reprocess any unsealed jars, or refrigerate and use them within a month.Before reprocessing a jar that didn't seal, check the following: Is there a crack or nick in the rim of the jar? If so, you will need to transfer the contents to a new jar. Is the lid new and unwarped? Was the lid properly centered on the jar? Was the rim of the jar clean?