Your quince jelly that did not set?

1. Not enough pectin. Pectin is a natural thickener that is found in fruits and vegetables. It is what causes jams and jellies to set. If your quince jelly does not have enough pectin, it will not set. You can add commercial pectin to your jelly to help it set.

2. Too much acid. Acid can prevent pectin from gelling. If your quince jelly has too much acid, it will not set. You can add baking soda to your jelly to neutralize the acid.

3. Not cooked to the right temperature. Jelly must be cooked to the right temperature in order to set. The correct temperature for jelly is 220 degrees Fahrenheit. If your jelly is not cooked to the right temperature, it will not set.

4. Too much sugar. Sugar can prevent pectin from gelling. If your quince jelly has too much sugar, it will not set.

5. Using under-ripe fruit. Quince that is not ripe enough will not have enough pectin to make jelly. Make sure to use ripe quince when making jelly.

If you have tried all of these things and your quince jelly still has not set, you can try re-cooking it. Bring the jelly back to a boil, and then cook it for an additional 5 minutes. This should help it to set.