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 thoroughly until shaggy dough forms and no dry flour remains visible.
03 - Transfer dough to lightly floured work surface. Knead vigorously for 8-10 minutes, incorporating vegetable oil during final 2 minutes, until smooth, elastic, and fully developed.
04 - Gently fold raspberries into dough, taking care to keep berries intact. Dough will appear sticky and display light pink marbling throughout.
05 - Place dough in lightly greased bowl, cover tightly with plastic wrap or damp towel. Let rise at room temperature for 6-8 hours until doubled in volume.
06 - Turn fermented dough onto lightly floured surface. Divide into 8 equal portions, approximately 4 ounces each, using kitchen scale for precision.
07 - Roll each portion into smooth ball. Create hole in center using finger or thumb, gently stretching to form 2-inch diameter ring. Arrange on parchment-lined baking sheet.
08 - Cover shaped bagels with clean towel. Allow to proof at room temperature for 1-2 hours until slightly puffed, or refrigerate overnight for enhanced flavor development.
09 - Adjust oven rack to center position. Preheat to 425°F.
10 - Bring 12 cups water to rolling boil in wide, deep pot. Add honey and optional baking soda, stirring until fully dissolved.
11 - Working in batches of 2-3, carefully lower bagels into boiling water. Boil for 45-60 seconds per side. Remove using slotted spoon, allowing excess water to drain before returning to prepared baking sheet.
12 - Immediately sprinkle Demerara sugar or press poppy seeds onto wet bagel surfaces for optimal adherence.
13 - Bake for 22-25 minutes until deep golden brown, rotating baking sheet halfway through cooking time for even browning. Transfer to wire rack and cool completely before slicing.