Stiff jams or jellies may result from
Always follow the manufacturer's directions for ingredients and precise cooking times found in the packages of commercial pectins. When making jelly or jam without adding purchased pectin, be sure to follow directions for determining doneness or the jellying point. See: http://www.uga.edu/nchfp/how/can_07/jelly_without_pectin.html http://www.uga.edu/nchfp/how/can_07/jam_without_pectin.html
Trying to remake a stiff jam or jelly for long-term storage is not expected to result in a quality product and is not recommended.
Suggested Uses for Stiff Jams or Jellies:
If a stiff jam or jelly was processed as recommended in a boiling water canner and the lid is vacuum sealed, the jar can be stored at room temperature like other jam or jelly. (Many homemade jams and jellies will keep with good quality up to one year. The quality loss may be quicker in light-colored and/or reduced-sugar products and it may be desirable to use these within 6-8 months.)
Hard-gelled preserves can be used as meat glazes. Warm the jam or jelly and spread it onto any type of meat during and after cooking. Discard any leftover jam or jelly glaze that came into contact with any meat that has not been fully cooked or utensils that came into contact with meat that has not been fully cooked.
Stiff jams or jellies can also be warmed for use as pancake or ice cream syrups.
Stiff jams or jellies can be thinned with water or fruit juice. They may or may not form a gel again once they are re-heated, as over-cooking of pectin can reduce or destroy its ability to form the gel structure. You will need to experiment with how much liquid is needed to thin your jam or jelly. It is best to work with only 2 to 3 half-pint jars at most at one time. Try four tablespoons (¼ cup) of liquid for each 8-ounce jar. Over very low heat, melt the stiff jam or jelly in the added liquid, stirring constantly to prevent scorching. When it is all in solution, raise the heat to medium and bring the mixture to a full boil, continuing to stir constantly. Remove from heat and quickly skim foam off jelly if necessary. Fill clean, dry containers for refrigerator storage. It is not recommended to re-process the remade jam or jelly in a canner and store it at room temperature. Jellies and jams thinned in this manner may or may not actually gel, but are likely to provide a mixture that that may spread more easily than the stiff product.
This document was prepared by the National Center for Home Food Preservation, July 2004.