into the released cell fluids and any added water They can’t simply re-form their gel for a couple of reasons Pectin molecules in water accumulate a negative electrical charge, so they repel each other rather than bond to each other; and they’re now so diluted by water molecules that even if they did bond, they couldn’t form a continuous network They need help to find each other again The cook does three things to cooked fruit to bring pectin molecules back together into a continuous gel First, he adds a large dose of sugar, whose molecules attract water molecules to themselves, thus pulling the water away from the pectin chains and leaving them more exposed to each other Second, he boils the mixture of fruit and sugar to evaporate some of the water away and bring the pectin chains even closer together Finally, he increases the acidity, which neutralizes the electrical charge and allows the aloof pectin chains to bond to each other into a gel Food scientists have found that the optimal conditions for pectin gelation are a pH between 2.8 and 3.5 — about the acidity of orange juice, and 0.5% acid by weight — a pectin concentration of 0.5 to 1.0%, and a sugar concentration of 60 to 65% Preparing Preserves Preserve making begins with cooking the fruit to extract its pectin Quince, apples, and citrus fruits are especially rich in pectin and often included to supplement other pectin-poor fruits, including most berries The combination of heat and acid will eventually break pectin chains into pieces too small to form a network, so this preliminary cooking should be as brief and gentle as possible (If a sparkling, clear jelly is desired, then the cooked fruit is gently strained to remove all solid particles of cell debris.) Then sugar is added, supplemental pectin if necessary, and the mixture rapidly brought to the boil to remove water and ...scientists have found that the optimal conditions for pectin gelation are a pH between 2.8 and 3.5 — about the acidity of orange juice, and 0.5% acid by weight — a pectin concentration of 0.5 to 1.0%, and a sugar concentration of 60 to 65%... sugar concentration of 60 to 65% Preparing Preserves Preserve making begins with cooking the fruit to extract its pectin Quince, apples, and citrus fruits are especially rich in pectin and often included... should be as brief and gentle as possible (If a sparkling, clear jelly is desired, then the cooked fruit is gently strained to remove all solid particles of cell debris.) Then sugar is added,