Method

1. Combine wheat flour, rye flour, dried rye sourdough, salt, and yeast in a mixing bowl.
2. Add the cold water and using spiral hook mix until a rough dough forms.
3. Knead for 4 minutes on slow speed, then 6 minutes on fast speed, until the dough is smooth and elastic.
4. Dough should be around 22 °C after kneading.
5. Place dough in a lightly oiled container, cover, and need to rest for 60 minutes total.
6. After 30 minutes, perform a gentle stretch-and-fold from all four sides.
7. Continue to rest the dough for another 30 minutes.
8. Turn dough onto a lightly floured surface. Divide into loaves as desired.
9. Pre-shape gently into rounds, cover, and rest for 15 minutes then shape into a tight round (boule) or oval (bâtard).
10. Place seam-side up in a floured proofing basket (banneton) or a bowl lined with a floured cloth.
11. Lightly dust the top with flour.
12. Proof at room temperature until the dough feels airy and springs back slowly when pressed. This usually takes 45–60 minutes.
13. Preheat oven to 230 °C with a tray inside, and prepare for steam.
14. Just before baking, turn the dough out seam-side down onto parchment or a peel.
15. Using a sharp lame or razor blade, score the dough at about 30–45° angle, cutting 0.5–1 cm deep.
16. Load the scored dough into the oven.
17. Add steam immediately by pour hot water into a tray at the bottom.
18. Bake at 230 °C for 25–30 minutes, until the crust is deep golden brown and crisp.
19. Remove from oven and cool completely on a wire rack before slicing.