Easy 30-Minute Blueberry Jam

For SHELF STABLE jam that you will store at room temperature and use a hot water bath to preserve:

1. Bring boiling-water canner, half full with water, to simmer. Wash jars and screw bands in hot soapy water. Pour boiling water over flat lids in saucepan off the heat. Let stand in hot water until ready to use. Drain well before filling.
2. Stem and crush blueberries thoroughly, with either of the methods explained in the post above.
3. With a dry measuring cup, measure exactly 4 cups of the prepared fruit into a large pot (6-8-quarts). Stir the pectin into the blueberries in the pot then add butter (reducing foaming).
4. Bring mixture to a full rolling boil (a boil that doesn't stop bubbling when stirred on high heat), stirring frequently. Stir in the sugar and lemon juice. Return the mixture to a full rolling boil and boil for exactly 1 minute, again stirring frequently.
5. Remove from the heat and skim off any foam with a thin metal spoon.
6. Ladle immediately into the prepared jars, filling to within ¼ inch of the tops. Wipe jar rims and threads. Cover with two-piece lids. Screw bands tightly.
7. Place jars on elevated rack in canner. Lower rack into canner. (Water must cover jars by 1 to 2 inches. Add boiling water, if necessary.) Cover; bring water to a gentle boil. Process 10 min.
8. Remove jars and place them upright on a towel to cool completely. After jars cool, check seals by pressing the middles of lids with your finger. (If lids spring back, lids are not sealed and refrigeration is necessary.)
9. Refrigerate this jam after opening when not in use.

For FREEZER JAM that you will store in the refrigerator or the freezer:

1. With a dry measuring cup, measure exactly 4 cups of the prepared fruit into a large pot (6-8-quarts). Stir the pectin into the blueberries in the pot then add butter (reducing foaming).
2. Bring mixture to full rolling boil (a boil that doesn't stop bubbling when stirred on high heat), stirring frequently. Stir in sugar. Return the mixture to a full rolling boil and boil exactly 1 minute, again stirring frequently.
3. Remove from the heat and skim off any foam with a thin metal spoon.
4. Ladle immediately into the prepared jars, filling to within ½ inch of the tops. Wipe jar rims and threads. Cover with two-piece lids. Screw bands tightly.
5. Allow the jam to sit at room temperature for 24 hours then refrigerate or freeze.
6. After the initial 24-hour resting time, keep jam refrigerated or frozen when not in use.