Ferment:

200g strong white flour
50g Dark rye flour
5g yeast (fresh if possible)
5g salt
175g Water

Bread:

500g Strong white bread flour
100g Dark rye flour
5g Yeast (fresh if possible)
15g Salt
400g Water
Flour for dusting

Ferment:

Mix the two flours together and rub in the yeast, using your fingertips as if making a crumble.
Add the salt and water, cover with cling film to ferment for 4-6 hours, or overnight in the fridge.
Bring back to room temperature before using.

Bread:

Preheat the oven to 250°C.

Use a scraper to scoop the ferment from its container into your bowl, all in one piece, and add the rest of your ingredients.
Work the dough until it is smooth, soft, supple and elastic, and not sticky.
Form it into a ball and place in a lightly floured bowl, covered with a tea towel, to rest for 1 hour.

With the help of the rounded end of your scraper, turn the dough out onto a lightly floured work surface and shape it into a ball again, put back in the bowl, cover and leave to rest for 1 hour.

Repeat the above step, but rest for 30 minutes.
Using the rounded end of the scraper again, turn the dough onto a well-floured work surface and divide it into two pieces of about 600g each.
Shape each into a ball.
Lightly flour two wicker baskets or line bowls with tea towels, well dusted with flour, and put a ball of dough in each one, seam side-down.
Cover with another tea towel and leave to prove for about 75 minutes, or until they have nearly doubled in volume.

Place the loaves on a peel or flat-eded baking tray, seam-side down, and cut a circle in the top of each loaf with a razor blade or sharp knife.
Mist the inside of the preheated oven with a water spray.
Quickly slide the loaves onto the baking stone or tray and bake for 5 minutes.
Turn down the heat 220°C and bake for a further 25-30 minutes until they are dark brown.
The loaves should sound hollow if tapped on the base with your finger.
Remove from the oven and cool on a wire rack.