01 - Combine active sourdough starter, lukewarm water, and sugar in a large mixing bowl. Stir continuously until sugar completely dissolves and mixture achieves uniform consistency.
02 - Add bread flour, whole wheat flour, and sea salt to starter mixture. Mix with wooden spoon until shaggy dough forms and no dry flour remains visible.
03 - Turn dough onto lightly floured work surface. Knead vigorously for 8 to 10 minutes, incorporating vegetable oil during final 2 minutes. Dough should become smooth, elastic, and slightly tacky but not sticky.
04 - Gently fold raspberries into dough using minimal pressure to preserve berry integrity. Dough will appear sticky with pinkish marbling throughout.
05 - Place dough in lightly greased bowl, cover with damp cloth or plastic wrap. Allow fermentation at room temperature for 6 to 8 hours until volume doubles in size.
06 - Transfer risen dough onto floured surface. Divide into 8 equal portions, approximately 4 ounces each.
07 - Roll each portion into smooth ball. Press thumb through center to create hole, then gently stretch and rotate to form uniform ring with 2-inch diameter opening.
08 - Arrange shaped bagels on parchment-lined baking sheet, cover with clean towel. Proof at room temperature for 1 to 2 hours, or refrigerate overnight for deeper sourdough flavor development.
09 - Position oven rack to center position. Preheat to 425°F.
10 - Bring 12 cups water to rolling boil in wide pot. Stir in honey or malt syrup until dissolved. Add baking soda now if using for extra chewiness.
11 - Carefully lower 2 to 3 bagels into boiling water. Boil for 45 to 60 seconds per side, then remove with slotted spoon, allowing excess liquid to drain. Return to prepared baking sheet. Repeat with remaining bagels.
12 - Immediately sprinkle boiled bagels with Demerara sugar or poppy seeds while surface remains tacky, ensuring adhesion.
13 - Transfer baking sheet to preheated oven. Bake for 22 to 25 minutes until bagels achieve deep golden brown color and sound hollow when tapped bottoms.
14 - Remove bagels from oven and transfer to wire cooling rack. Allow to cool completely for at least 30 minutes before slicing or serving to preserve texture integrity.