If a jelly does not set properly, it can be used as a syrup on pancakes or waffles. It can also be used in desserts and cooking.
An attempt can also be made to reset the jelly. This is done by placing it back into the pot and adding sugar, pectin and lemon juice. The mixture then needs to be recooked and reprocessed. This may result in a more rubbery texture, and the results can vary.
In order for jelly to properly set, it needs to be allowed to completely cool. Some types of jelly take longer than others to gel.