Soak: Shake the flowers over the sink to remove any insects or dust. Place in a large bowl and cover with the juice. Cover the bowl and let it stand in a cool place for 24 hours (not in the fridge).
Preparations: Place a small plate in the freezer; you will need it to check if the jelly is set. Sterilize the jars and lids and place them upside down on a clean kitchen towel.
Mix: Strain the flavored juice through a fine-mesh sieve into a large pot. Add the lemon juice. Mix the sugar and pectin in a small bowl. (See note). Whisk the sugar-pectin mixture into the juice in the pot.
Cook: Bring to a boil while stirring often. Once the mixture comes to a full boil, cook for 4 minutes while stirring continuously.
Check: Remove the pot from the heat. Pour a few drops of jelly on the plate you had in the freezer. If they set almost immediately, the jelly is ready. If they remain very liquid after one minute, boil the jelly for another minute and check again, it should be fine now, don’t overcook it, or it will become too solid.
Transfer: Pour the jelly into the sterilized jars. It is preferable to use a jam funnel; it makes filling more manageable and safer (Amazon affiliate link). Seal the jars and let them cool before moving.
Store in a dark, cool place, like a cellar or pantry. It will keep for at least 6 months and up to 1 year. Once you open a jar, keep it refrigerated and consume within 2-3 weeks.
Always use pectin according to the packet’s instructions. If the instructions regarding the needed amount of pectin, the way of using it, or the cooking time differ from mine, make sure you follow the instructions on the packet.