Fill canner halfway with hot water, cover, and pre-heat to 180°F(simmering) for hot pack.
Heat canning jars in hot water until ready for use; however, do not boil!
Place flat lids in a small saucepan and bring to a simmer over low heat until ready to use – do not boil. Set bands aside.
Puree peppers in a food processor or blender with 1 cup cider vinegar until smooth. Do not strain purée.
In a large stainless-steel saucepan, combine purée with the remaining 1 cup cider vinegar and sugar. Bring to a boil over high heat. Boil 10 minutes, stirring frequently.
Add liquid pectin, immediately squeezing entire contents from pouches. Continue to boil hard for 1 minute, stirring constantly. Remove from heat. Add food coloring, if using, and skim foam if necessary.
Ladle hot jalapeño jelly into hot jars one-at-a-time, leaving ¼inch headspace. Remove air bubbles with a straight spatula. Wipe jar rim/threads using a clean damp cloth/paper towel to remove any food residue.Center the lid on jar. Apply band until fit is “fingertip” tight.
Place jars in canner rack and lower rack into water. Make sure 1-2 inches of water covers jars, add more hot water if necessary. Place lid on the canner and bring to a full rolling boil. Once at a rolling boil, set timer and begin processing time. Process in a boiling water canner for the appropriate time according to the altitude chart.
Once processing time is complete, turn off the heat, remove thecanner lid, and wait 5 minutes before removing jars.
Remove jars from canner without tilting and set upright on a towel with 1 inch space between jars to prevent jar breakage. Leave jars undisturbed for 24 hours. Do not re-tighten bands or push on the center of lids!
Check lids for a good seal after 24 hours. The lid should not flex up and down when the center is pressed. If it does, refrigerate the jar and use food within two days.
Remove bands. Clean the jars, label, and store in a cool, dry,dark place. For best quality, consume within one year.
For a hotter jelly, tie the seeds in a square of cheesecloth. Add with the sugar and cook as directed. Discard the bag just before adding the pectin.