Learn how to make the best strawberry rhubarb jam with this easy recipe. You can achieve the perfect set without adding pectin as long as you follow the ingredients quantities listed below and boil to the jam setting point.
Sterilize jars in the oven at 250 °F while you make this recipe. Store the jars in the oven. Have the lids on hand and ready. See notes below for details..
Chop the berries in half or quarter if they are large. Slice the rhubarb into 1 inch pieces (more or less).
Mix the berries and rhubarb with the sugar, lemon juice, and the split vanilla bean (if using) in a big pot.
Cover the mixture and let the fruit macerate at room temperature for 30 minutes, stirring every 10 minutes with a wooden spoon to help the sugar dissolve.
Place the pot on the stove, uncovered and bring the mixture to a boil, stirring occasionally. If you notice that a stable foam forms on the surface of the jam as it boils, you can skim it off the top with a spoon to remove it. This way your jam will be clear and free of too many air bubbles.
When the jam comes to a boil, continue cooking it until it hits the jam setting point, around 104 ºC (220 ºF). For a softer set, you may boil until the jam reaches 103 °F (217–218 °F).
Remove from the heat. Let the pot of jam stand 5 minutes off the heat to cool slightly and thicken, then stir to distribute and suspend the fruit more evenly.
Divide the jam among the jars, leaving a ¼ inch headspace. Remove air bubbles, wipe the rims clean, then cover with the lids, fingertight. If any of the jars aren't filled full, don't seal them. Instead you can cover them and enjoy them right away, storing in the fridge.
Seal the closed jars according to the manufacturers recommendations, by inverting the hot jars for 2 minutes before placing upright or use a water bath canning kit to seal the jars.
Let sit 24 hours undisturbed before storing them in the pantry.
Notes
This recipe makes 4–5 jars (of 250 mL (1 cup) each)To sterilize your jars: wash them well with soap and water if they aren't clean or are new, then place on a sheet pan in the oven, and heat them at 250 °F for at least 30 minutes. Leave them in the hot oven until you are ready to use them.If you notice that a stable foam forms on the surface of the jam as it boils, you can skim it off the top with a spoon to remove it. This way your jam will be clear and free of too many air bubbles.