Step 1: Sterilize your canning jars and lids according to standard canning procedures. Keep them hot until ready to fill. Have all your equipment, including jar lifters, a canning funnel, and a large pot for the jelly, ready.
Step 2: Wearing gloves, wash and prepare the peppers. Remove stems from bell peppers and jalapeños. Halve jalapeños and scrape out seeds and membranes for milder jelly (leave some in for spicier). Finely chop all peppers using a food processor or by hand. You should have approximately 1.5 cups of bell peppers and 1.5 cups of jalapeños.
Step 3: In a large (at least 6-quart) heavy-bottomed pot, combine the finely chopped peppers, apple cider vinegar, and powdered pectin. Stir well to ensure the pectin is dissolved.
Step 4: Bring the mixture to a full rolling boil over high heat, stirring constantly to prevent sticking. A ‘rolling boil’ is one that cannot be stirred down. Boil for exactly 1 minute.
Step 5: Immediately add all 5 cups of granulated sugar to the boiling mixture. Stir continuously and vigorously until the sugar is completely dissolved. Return the mixture to a full rolling boil, stirring constantly.
Step 6: Once a full rolling boil is reached again, boil for exactly 1 minute. Remove the pot from the heat.
Step 7: (Optional set test) Spoon a small amount of hot jelly onto a cold plate (chilled in the freezer). Wait 1-2 minutes, then push the jelly with your finger. If it wrinkles, it’s ready to set. If not, return to heat and boil for another minute, then re-test.
Step 8: Carefully ladle the hot jelly into the hot, sterilized jars, leaving 1/4 inch of headspace. Wipe the rims clean with a damp cloth to ensure a good seal.
Step 9: Center the lids on the jars and apply the bands, tightening them until fingertip-tight. Place the filled jars into a boiling water canner, ensuring they are covered by 1-2 inches of water.
Step 10: Bring the water to a rolling boil and process the jars for 10 minutes. Adjust processing time if living at higher altitudes (add 1 minute for every 1,000 feet above sea level).
Step 11: After processing, carefully remove the jars from the canner and place them on a towel-lined counter, spaced apart. Do not disturb for 12-24 hours. Listen for the ‘pop’ of the seals.
Step 12: Check seals once cooled. Lids should be concave and not flex when pressed. Store properly sealed jars in a cool, dark place for up to 1 year. Refrigerate any unsealed jars and opened jars.