Mix the water, apple cider vinegar, salt and yeast in a container, preferably stirring with a wooden spoon.
Knead into a dough with the flour and place in a greased baking pan, or form a loaf and place on a baking sheet.
Place the bread in a cold oven and bake at 200°C top/bottom heat for about 1 hour. In between, brush the bread with a little salt water to get a nice brown and crispy crust.
This process can be repeated.
Then leave to cool in the oven for 10 minutes. Tip:
If desired, use other types of flour or change the proportions of each type of flour.
Nuts or other grains can be added according to taste.