8 -oz (250 mL) jars
Prepare canner (water bath). Sterilize jars and lids.
In a large, deep saucepan, stir berries with sugar. Bring to a boil over medium heat, stirring constantly to dissolve sugar. Boil, stirring frequently, until mixture thickens. Remove from heat and test gel. If gel stage has been reached, skim off foam.
Ladle hot jam into sterilized jars, leaving 1/4-inch (0.5-cm) headspace. Wipe rim. Centre lid on jar and screw on metal band.
Place jars in canner, ensuring they are completely covered with water. Bring to a boil and process 10 minutes. Remove canner lid. Wait 5 minutes, then remove jars, cool and store.