Learn how to can delicious Strawberry Rhubarb Jam for long term storage! The recipe will yield approx. 9 jars of yummy, sweet and tangy jam!
Begin heating water in canner, and prep/heat jars, lids and rings per manufacturer instructions, so they're ready when the jam is ready.
Place strawberries in large bowl; crush them well before measuring. Rhubarb should be thinly sliced before measuring, as well.
Measure exact amount of crushed strawberries and sliced rhubarb into a large stockpot or Dutch oven. Add fresh or bottled lemon juice and pectin. If desired, add butter to reduce foam as jam cooks (optional), Stir to combine ingredients.
In a separate large bowl, put the granulated sugar. You need it ready to go as soon as the jam is boiling hot. Set aside.
Bring fruit mixture to a FULL ROLLING BOIL on HIGH heat. NOTE: A full rolling boil means fruit doesn't stop boiling, even while stirring. Stir fruit constantly while it cooks. As soon as fruit comes to full rolling boil, dump ALL sugar in at once. Stir very well, to combine. Bring jam back to a FULL ROLLING BOIL, stirring constantly, and let it boil for 4 minutes. When done, remove pot from the heat. If there's any foam on top, skim it off and discard.
Ladle jam into clean, pre-heated jars. Fill each with jam (using canning funnel if possible). Leave 1/8" headspace remaining at the top of each jar. Remove air bubbles from by inserting a non-metallic utensil down the sides of the jar several times. Wipe jar rims very well with a wet paper towel or dishcloth to remove any jam residue that could cause jar lids to not seal properly. Cover jars with prepared flat lids; add screwband and tighten to fingertip tight.
Once sealed, place jars carefully on canning rack. Lower rack into simmering water in canner. Make sure water covers top of the jars by 1-2 inches, adding more hot water, if necessary. Cover the canner. Bring water to a gentle boil. Once gently boiling, set a timer and process jam for 10 minutes. When done, remove pan from heat, remove cover, and let jars sit for 5 minutes in the hot water.
Remove hot jars; place upright on a dish towel on the counter. DON'T place HOT jars directly on countertop; temperature variances could cause jars to crack. Let cool, undisturbed, 12-24 hours. As jars seal, you should hear a "ping" sound. Once jars have cooled, test the seal before storing jars in pantry. To test seal: press center of each lid with an index finger. If lid springs back, jar did not seal properly, so you must refrigerate that jar of jam. It's fine for eating, but cannot be stored long term in pantry. If jars sealed properly, wipe clean, remove the screwband for storage; label jars. Place jars in pantry for long term storage.
Strawberry Rhubarb Jam https://www.thegratefulgirlcooks.com/strawberry-rhubarb-jam/