Best Strawberry Rhubarb Jam (for canning!)
This strawberry rhubarb jam is bursting with sweet and tart flavors, fruit forward and delicious with a hint of vanilla! No commercial pectin is needed to make this jam set. It cooks on the stovetop until thickened with the help of sugar and lemon juice, then water bath canned to be preserved.
Yield: 5 half pints
Ingredients
- 2 pounds rhubarb, cut into 1/2 inch pieces
- 1 pound strawberries (not over ripe), stems removed and cut into 1/4 inch pieces
- 2 1/2 cups granulated sugar*
- 3 tablespoons bottled lemon juice (Bottled is used because the acidity is 5%, fresh lemons vary. This is important for the preservation.
- 1/4 teaspoon fine salt
- 1 vanilla bean pod, seeds scraped out
Instructions
- Combine rhubarb, strawberries, and sugar in a large glass bowl. Stir thoroughly to combine. Cover with plastic wrap and refrigerate for at least 12 hours, up to 24. This allows the fruit to macerate and release all of its juices.
- When ready to can, take your fruit out of the refrigerator. Add seeds of the vanilla bean. Prepare your jars by washing them with soapy water. Add them to your water bath canner with the wire rack, and bring to a simmer while you make the jam. This is because you want your jars to be hot when you fill them with jam. Place a small plate in the freezer (this helps to test the set.)
- To make jam, add rhubarb mixture that sat overnight to a large heavy bottomed pot. I like to use my 5.5 quart dutch oven. Add the lemon juice and salt. Bring to a boil over medium high heat, stirring occasionally.
- Once the mixture starts boiling, it will begin to foam. Stir every few minutes, watching the heat. The juices will be simmering rapidly as the jam continues to cook down and thicken, evaporating some of the liquid. Over the next 10 minutes, watch the heat as the jam starts to become more cohesive and the fruit breaks down.
- Towards the 22 to 25 minute mark, the jam will begin thickening even more. (Note, this will also depend on your fruit. If it was a wet harvest, your fruit wil have more moisture and take longer to cook down.) Stir often, scraping the sides to ensure it doesn't burn, and watch your heat. I like to start using a thermometer at this point, aiming getting to 212ish degrees F for this jam to turn out with the lovely thick consistency you see in the photos, but you don't have to use a thermometer. Rather, the jam will slide off the spoon in a sheet, rather than individual droplets when it's about ready. Once you think that your jam has reached its setting point, spoon a bit of the jam on the cold plate from the freezer and tilt it vertically so the jam runs. You are aiming for a slow descent, not a runny mess. If it runs slow, it’s set! You can also let the spoonful of jam sit on the cold plate for 30 seconds and then push it with your spoon or finger. If it doesn't flood back together, just creeps back into the open space, you’ve reached your setting point. If it does not do these things, continue cooking.
- When jam is thickened, take each warm jar out of the water and set on a kitchen towel. Fill with hot jam, leaving 1/4 inch headspace. Screw the lids on until finger tight, and put jars back in the water bath canner.
- Once you’ve filled all jars, return them to the canner and bring the water to a boil with lid on. Process for 10 minutes, then turn heat off and leave jars in canner for 5 minutes before removing.
- Let fully cool on a kitchen towel on the counter, and let them seal. Store in a cool, dark place for 1 year.
Notes
- DO NOT reduce the amount of sugar in this recipe or it will not set. The jam is not too sweet, trust me. The tart rhubarb is the perfect balance.
- It's OK to halve to halve this recipe, but do not double, as the mixture would need to cook for too long a time, and possibly affect the set of the jam.