Home-canned cooked jam can separate. When this happens the fruit ends up at the top of the jar and the jelled portion at the bottom. This is a fairly common occurrence, especially for cooked strawberry jam. Jam that separates is perfectly safe to eat. The jam separated because of the difference in the density between the liquid and the pieces of fruit.

Michigan State University Extension offers the following six tips to prevent jam from separating:

1. Always use ripe fruit.
2. Crush the berries up into very small pieces.
3. Cook the jam the recommended amount, do not undercook it.
4. When the jam is removed from the heat, gently stir it, off and on, for about 5 minutes and then put it into the jars to process. It will still be very hot.
5. You can process the jam in either a water bath canner or a steam canner. When processing time has been reached, lift the jar rack, full of jars, above the water in the water bath canner and let them sit there for 5 minutes before moving them to a cooling rack. After the processing time has been reached in a steam canner, take the lid of the canner partially off and let the jars sit in the canner for 5 minutes before cooling the jars on a rack.
6. Jars should seal fairly quickly. If you see the jam starting to separate after the lids have sealed, gently turn the jars upside down. In an hour, gently turn them right-side up. Continue this process until it is evident that the jam will not separate.

If jam has separated, such as in the picture, simply stir it up when you open the jar of jam, and it will stay mixed and not separate again.

When preserving food at home always follow directions carefully and use research-based recipes found in updated Ball Blue Books, So Easy to Preserve and the USDA Complete Guide to Home Canning and Preserving and current resources from Extension organizations.