Clear out a work area or your kitchen top, you will need this to knead the dough. (Warning, can be a bit messy... I know it!)
Place the 350g of spelt flour and 300 grams of whole grain wheat flour on the work area. Have it be a pile, with a hole in the middle.
Pour the water, salt, flaxseed and the dough from Part 1 in the middle and start kneading from the middle. Take small parts of flour from the sides every time until everything is properly mixed. When you have a ball keep kneading for about 10 minutes and make sure to pull and stretch the dough properly until it's a smooth dough.
Put the dough in a big glass/ceramic bowl and cover with a damp tea towel. Let it ferment for 10 hours at room temperature.
After 10 hours, cover the working area in flour and place the dough on top. Mold it into a ball and cover with a damp tea towel. Let it rest for 1 hour.
After 1 hour, flatten the dough once with your hand and make it oval. Tuck the sides in under the dough. Place the dough on a oven tray that's covered in baking paper. Cover with a damp tea towel and let it rest for 3 hours.
After 3 hours, make small cuts at the top of the dough with a sharp knife.
Put a bowl of hot water in the oven and place the oven tray above it in the middle of the oven. Turn the oven on at 190 degrees Celcius (hot air). When the oven heats up, the dough will keep rising.
Bake the bread for about 65 minutes. You can tell when it's done, if it sounds hollow when you knock the bottom.
Put the bread on a cooling rack to make sure moisture can evaporate for at least 30 minutes.If you don't do this, the crust will not be crispy.
Slice the bread in your desired portions, and enjoy!