Put corncobs in pot of water.
Bring to a boil. Boil for 35-40 minutes.
Strain liquid through double cheesecloth.
Start by preparing jars and getting water in the canner heating. You want the canner hot, but not boiling, when the jars are ready to be processed.
Measure out 3 cups of strained liquid. Stir in the pectin and bring to a boil.
Add the sugar all at once, which will likely stop the boil. Bring back to a boil while stirring.
Boil 5 minutes, stirring constantly. Remove from the heat.
Skim foam if needed.
Put hot jelly into hot jar, leaving ¼” headspace.
Remove air bubbles, wipe rim clean, and place seal and ring.
Place jar in the warm canner. Proceed to fill all jars.
Process according to directions.
