Combine the apple juice and blue spirulina in a pot and whisk well. Sprinkle over the gelatin. Allow to sit for 5 minutes to harden.
Transfer to the stove and heat on medium-low for 2-3 minutes until the mixture returns to liquid.
Use a dropper to transfer the gummy mixture into a mold of your choice (like this) and fill only half way. Set aside the rest of the apple juice mixture and transfer the gummy mold to the freezer to set for about 10-15 minutes.
Add the grape jam to a piping bag and slice off the tip.
Once the base of the gummies are set, remove from the freezer. Add a small dot of filling into the center of each gummy.
If the rest of the apple juice mixture has set, place it back on the stove for a minute or so (whisking well) to return it to liquid. Allow to cool slightly before using a dropper to fill the rest of the gummy molds, ensuring that the jam is covered.
Return the full gummy molds to the fridge and allow to set for 3-4 hours. Store in the fridge and enjoy!
Notes
If you want the gushers to be even more sour, add a citric acid coating!