In a large bowl, combine the whole wheat flour, bread flour, yeast, salt, and warm water.
2 cups whole wheat flour, 2 cups bread flour, 8 g salt, 5 g instant yeast, 1 1/2 cups water
Knead the dough for 5-7 minutes until smooth and elastic.
Place the dough in a bowl, cover, and refrigerate overnight (12-18 hours).
Remove the dough from the fridge and shape it into a loaf.
Place the shaped dough in a greased or baking paper lined loaf pan, cover, and let it rise in a warm place for 1-2 hours. Score the loaf. You can bake the bread on a baking sheet lined with parchment paper or in preheated a Dutch oven as well.
Preheat your oven to 410°F (210°C). Cover the loaf tin with tin foil and bake the bread for 20 minutes. Remove the foil and bake it for a further 20 minutes. Let it cool in the loaf tin for 5 minutes before removing it. Let it fully cool on a wire rack before slicing.
Notes
Temperature: Ensure the water is lukewarm rather than hot to activate the yeast. Avoid using cold water, as it can slow down the fermentation process.Patience: Cold fermentation takes time. Allow the dough to ferment in the fridge for a minimum of 12 hours and up to 3 days.Final proof: Don't skip the final proof. It is essential for a well-risen and flavorful loaf.Storage: Store leftover bread in an airtight container at room temperature for up to 3 days or in the freezer for longer.