The pH and sugar are important parameters for settling of jelly. The amount of pectin can be determined by alcohol test or jelmeter test which helps to indicates how many parts of sugar are to be added to one part of juice. The final jelly should contain at least 0.5 % acid but not more than 1% because more amount of acid leads to syneresis in jelly. Sugar imparts sweetness as well as body. If the level of sugar is high jelly retains less water which results in stiff jelly because of dehydration.
Prolonged boiling of jelly leads to inversion of sugar and destruction of pectin. The end point of boiling can be judged by sheet or flake test, drop test, or temperature test.