01 - Whisk together the active sourdough starter, lukewarm water, and sugar in a large bowl until fully dissolved.
02 - Add bread flour, whole wheat flour, and sea salt to the starter mixture. Mix with a wooden spoon until shaggy dough forms.
03 - Turn dough onto lightly floured surface and knead for 8-10 minutes until smooth and elastic. Drizzle with vegetable oil during the final minute of kneading.
04 - Gently fold raspberries into the dough using minimal pressure to keep berries whole. The dough will appear sticky with a marbled pink effect.
05 - Place dough in a greased bowl, cover with plastic wrap, and let rise at room temperature for 6-8 hours until doubled in size.
06 - Turn risen dough onto floured surface and divide into 8 equal portions using a dough scraper or knife.
07 - Form each portion into a smooth ball. Poke thumb through center and gently stretch opening to create bagel shape, ensuring even thickness.
08 - Arrange bagels on parchment-lined baking sheet, cover with clean towel, and proof for 1-2 hours at room temperature. For enhanced flavor development, refrigerate overnight.
09 - Set oven to 425°F approximately 30 minutes before baking to ensure proper temperature.
10 - Bring 12 cups water to boil in wide pot. Stir in honey or barley malt syrup and baking soda if using until dissolved.
11 - Cook bagels in boiling water for 45-60 seconds per side. Remove using slotted spoon, allowing excess water to drain before returning to baking sheet.
12 - Immediately sprinkle with Demerara sugar or poppy seeds while bagels are damp from water bath to ensure adhesion.
13 - Bake for 22-25 minutes until deep golden brown. Rotate baking sheet halfway through for even browning.
14 - Transfer bagels to wire rack and cool completely before slicing or storing to preserve texture.