Place the blueberries in a small simmer pot on low until juices begin to pool at the bottom. Increase the heat to low-medium keeping a close eye so it does not burn.
Reduce the blueberries until you have about 1/2 cup of blueberries and juices remaining. Set the blueberry reduction to the side to cool while you gather the other ingredients for the bagel dough.
In the bowl of a stand mixer, combine the active starter, flour, salt, warm water, dried blueberries, and reduced blueberries (be sure it has cooled down and is not hot.) Mix on low speed (number 2 for a KitchenAid mixer) for about 5-10 minutes or until the dough pulls away from the sides and is no longer sticky.
Place the dough in a greased bowl, cover with plastic wrap, and let it rise at room temperature for 8-12 hours or until doubled in size.
Once the dough has doubled, remove the dough from the bowl onto a clean surface. Remove air bubbles by pressing the dough flat into a circle. Divide it into 8 equal portions using your bench scraper.
Gather the edges of the dough, bringing them inwards to form a ball and pinch tightly. Flip the dough over with the pinched side on the work surface. Use your hand and work surface to create tension on the top of the dough by pulling the dough towards you while turning the ball slightly. Do this several times until the top is tight and smooth.
Cover the dough balls with plastic wrap or a damp tea towel and allow them to rest for 5 minutes before moving onto the next part of the shaping process.
Then use your fingers or thumbs to poke a hole in the center of the dough ball and gently stretch to form a bagel shape. Spinning gently around your two pointer fingers in a circle helps stretch the dough evenly.
Place the shaped bagels on a parchment-lined baking sheet.
Cover the shaped bagels loosely with plastic wrap and let them rise for another 1-3 hours, or until slightly puffy. Do not overproof. They will puff up more when boiled and baked.
After the bagels have become puffy, preheat the oven to 350°F and bring a large pot of water to a gentle boil.
Add the baking soda and brown sugar to the boiling water.
Carefully transfer the bagels, using the parchment paper, into the boiling water. As soon as the parchment paper hits the water it will release the bagel easily and will prevent the dough from collapsing. Boil a few at a time for 1 minute per side.
When you first place the bagel in the water, use a chopstick to swirl inside the bagel hole to prevent it from closing up completely.
Use a slotted spoon to remove the boiled bagels and place them back on a parchment-lined baking sheet.
The bagels will drastically change in color once they are boiled. the outside looks very dark, but don't worry the inside still has a beautiful purple, blue color.
Once all the bagels have been boiled, transfer the baking sheet to the preheated oven.Bake for 20-25 minutes, or until the bagels are golden brown and sound hollow when tapped on the bottom. Allow the bagels to cool on a wire rack before slicing.