Wash and seed peppers; chop in food processor or grind in blender or meat grinder. Add enough pepper pulp to the vinegar and lemon juice to make four cups. Mix in a large kettle with sugar, salt, and chili powder. Bring to a full rolling boil, stirring constantly. Remove from heat and add liquid pectin. Return to heat and boil hard for 1 minute; turn heat down to simmer. Stir and skim off foam for 5 minutes more as mixture boils gently. Pack in hot sterilized 8-ounce jars; seal and let cool on counter top. Store in refrigerator up to 1 year.
