Prepare Peppers: Wear gloves to handle jalapeños. Wash and finely chop all peppers (2 1/2 cups total).
Cook Peppers: In a large saucepan, combine peppers and vinegar. Bring to a boil, then simmer for 10 minutes, stirring occasionally.
Add Pectin: Mix 1/4 cup sugar with Sure Jell pectin. Stir into the pepper mixture until dissolved. Add butter if using.
Add Sugar: Stir in remaining sugar. Bring to a full rolling boil over high heat, stirring constantly.
Boil: Boil for 1 minute, then remove from heat. Skim foam and add food coloring if desired.
Test Gel: Spoon a small amount onto a chilled plate. If it wrinkles when pushed, it’s ready.
Jar: Ladle into sterilized half-pint jars, leaving 1/4 inch headspace. Wipe rims, secure lids, and process in a boiling water canner for 10 minutes.
Cool: Let jars cool for 12–24 hours. Check seals before storing.
