This is because pectin can take that long to develop firm set. If after 48 hrs your marmalade is still very runny, here is what to do: Open all your jars up again and pour into large stock pot. ... If you are still not achieving the right set, add more powdered pectin (1 extra teaspoon at the time), re-boil and test again.

What can I do if my marmalade won't set?

As I mentioned, you can save and fix a marmalade that doesn't set properly because it's undercooked by reheating the preserve, bringing it back up to a boil and cooking to 220ºF–222ºF before transferring to sterilized jars and sealing.

How do you fix runny orange marmalade?

Add 2 teaspoons of powdered pectin, 1 tablespoon of store-bought lemon juice, 1/4 cup of water and 4 tablespoons of white granulated sugar and to a heavy-bottomed saucepan for every 1 cup of orange marmalade you need to fix and bring it to a boil, stirring continuously with a heat-proof spoon.