Begin by rinsing your blueberries really well with cold water. Be sure to remove any stems you see. Place a saucer in the freezer to get really cold.
Finely dice the jalapeño peppers. I removed the stems and dice the whole thing seeds and all. They’ll be removed later with the siv.
In a large saucepan, combine the blueberries, jalapeños, sugar, and lemon juice over medium heat. Bring everything to a low boil until the sugar is dissolved and the berries begin to burst. Stir constantly to prevent the jam from scorching.
While you’re stirring, mash the berries with a spoon to create more juice.
After the sugar has dissolved, reduce the heat to simmer. Continue to simmer stirring occasionally until the jam thickens.
Perform the saucer test on the jam to see if it’s set.
Place a siv top of a large mixing bowl and strain the jam through it. This will remove any skins and seeds from the jam leaving it smooth.
After straining, use the jar funnel to spoon it into the clean half-pint jars. Be sure to clean the rims with white vinegar before adding the lids.
At this point, the jam is ready once it cools and sets. You can put it into the fridge where it will keep for around 4 weeks.
You can also seal it using a water bath canning method. Process half pints for 10 minutes using this method.