Setting tests

A keeping jam should have 60% added sugar content or three parts sugar to five parts jam. Some jams are ready for setting after only 5 minutes boiling; others take 10–15 minutes, and a few take longer. A setting test should be made early, as some fruits lose their setting qualities if jam is boiled too long and if this happens the jam will never set. When the jam reaches setting point, remove it from heat at once.