Rye Levain: Combine starter, water, and rye flour. Let sit at room temperature until doubled in volume.
Hot Soaker: Mix dark rye flour, flaxseed, hot coffee, hot water, and barley malt. Leave overnight in a warm oven.
Preferment: Mix rye levain with hot soaker and let ferment.
Dough: Combine all ingredients and knead in a mixer. Let the dough ferment, then bake in a preheated oven.
