The fruit may float to the top if the fruit was:

• underripe
• not fully crushed
• undercooked or cooked too slowly

Some tips may be to:

• Follow the recipe exactly
• If using added pectin, use the instructions for the brand of pectin being used. If not using added pectin, choose 1/4 slightly under ripe fruit and 3/4 fully ripe fruit and follow directions.
• Boil jam rapidly
• Make only one batch of jam at a time; do not double the recipe.
• Sterilize jars by boiling them for 10 minutes (this way you only need to process them in a water bath canner for 5 minutes)

You also may want to try the following:

• Once the jam has cooked, remove from heat and stir an additional 5 minutes
• Hold the ladle very close to the jar when pouring the jam into the jar