Michigan State University Extension
Preserving Food Safely - 01600543
JELLY: is made from strained fruit juice. The product is clear and firm enough to hold its shape when turned out of the container, yet soft enough to spread.
BUTTERS: are made by cooking fruit pulp and sugar until thick enough to spread easily. Spices are added depending on personal taste. The butter needs to be cooked slowly after the sugar is added to prevent scorching. Finer butters can be made by straining the pulp through a food mill and then through a fine-meshed sieve.
JAM: is made from crushed or ground fruit and tends to hold its shape but is generally less firm than jelly. Jams are cooked until they round up in a spoon. They should be made in small batches and cooked rapidly until the sugar dissolves.
CONSERVES: are jams made from a mixture of fruits, usually including citrus fruit; often raisins and nuts are added. Conserves are cooked until the mixture will round up in a spoon. They should be made in small batches and cooked rapidly.
MARMALADE: is a tender jelly with small pieces of fruit or peel distributed evenly throughout. It should be cooked in small batches and brought quickly to the jellying point after the sugar is added. A marmalade commonly contains citrus fruit; part of the white rind should be cooked with the fruit for most of the pectin is found there.
PRESERVES: are whole fruits or large pieces of fruit in a thick syrup, often slightly jellied. Preserves should be cooked in small batches in wide pans. If the syrup gets too thick before the fruit is tender and clear, add boiling water. If the fruit is clear and tender but the syrup is too thin, remove the fruit and cook the syrup rapidly to the desired consistency.