This article is from the Food Preserving FAQ, by Eric Decker firstname.lastname@example.org with numerous contributions by others.
a. Using overripe fruit. b. Packing fruit too loosely.
c. Syrup too heavy.
d. Processing too long. Pectin is damaged.
e. Processing at too high a temperature (pressure canner).
f. Raw packing. Raw food contains a lot of air.
g. Smashing or pureeing food prior to heating it activates enzymes which
break down pectin in the juice so the food pieces are lighter and rise to
the top. Heat or crush while heating any foods to be pureed or food to be
packed in its own juice to help prevent separation.
Prepared by Susan Brewer/Foods and Nutrition
Specialist/Revised, 1992 EHE-665 ----