In a large mixing bowl, combine warm water, pickle juice, and active sourdough starter until well blended. Gradually add bread flour and dark rye flour, stirring until a shaggy dough forms. Knead in fine sea salt. Cover and let rest for 45-60 minutes.

Perform a series of 'stretch and fold' techniques on the dough every 30 minutes, incorporating dill pickles during the third stretch. Repeat for a total of four times over the next 2 hours.

Cover the bowl tightly and let the dough rise in a warm place for about 2 hours until it doubles in size.

Gently turn the dough onto a floured surface. Shape it into a batard or boule and rest for 20 minutes.

Place the shaped dough seam-side up in a floured banneton. Cover with a kitchen towel and refrigerate for 2 hours or up to 3 days.

Preheat your Dutch oven to 450°F (230°C). Score the dough and bake covered for 30 minutes, then uncovered for an additional 10-15 minutes until crust is caramel colored.

Transfer the loaf to a wire rack to cool for at least 2 hours before slicing.