Mix the flour together with the yeast. Add the vinegar and the water and mix together well until a homogeneous mixture is formed. With flour-coated hands, form a round loaf of bread and place it on a baking tray that has been covered with greaseproof paper (wax paper). Cover with a damp cloth and leave in a warm place to rise for about 1 hour. Bake in the preheated oven at 200°C (400° F. / Gasmark 6) for about 10 minutes, then reduce the heat to 180°C (350° F. / Gasmark 4) and bake for an additional 30 minutes.