Pick the stem off the Grapes and discard, clean the grapes with purified water and drain. Place them into a large stainless steel pot with a little bit of water just to cover the bottom. Bring to a boil over high heat, add grapes and mash. Reduce heat to med low and continue mashing until your grapes are all mashed. Remove from heat and cover.
Strain your juice through a double thickness of damp cheesecloth.Let in hang over a large bowl for 1 hour. Pour juice into a large pot. Bring to a boil and add Sugar and pectin allow to hard boil for 1 minute. Don't over boil.
Heat mason jars on a pan in the oven face down with a layer of water. The tops of mason jars can be heated on top of the stove in a pot with boiling water. Place lids on counter on top of a cloth.
Using a wide mouth funnel pour grape juice into hot sterile jars and put lids and screw on top tightly. Let jars cool overnight on the counter. Grape juice will turn into jelly in 12-24 hours.
Video
Notes
I recommend you get the pink box of pectin when using less sugar to help it thicken well.