Making a sourdough starter at home usually takes days of feeding and waiting. This Dr. Oetker sachet shortcuts the process: it is a dry yeast that combines dried sourdough powder with baker's yeast and wheat malt flour, so you can bake a tangy loaf in a single afternoon. It is made with gluten-containing cereals (wheat, and in the manufacturer's current recipe also rye), so it is not suitable for a gluten-free diet.
One sachet is meant for 500 g of flour. Sift the flour into a deep bowl, stir in the contents of the sachet with salt and sugar, add water and olive oil and mix for about a minute with the dough hooks of a mixer, then knead by hand until the dough no longer sticks. Cover with a damp cloth and let it rise for about two and a half hours until doubled in size. Shape it into a round loaf of 16 to 18 cm, score the top in a few places, rest it for 30 minutes more and bake in a preheated oven at 180 degrees C for roughly 35 to 45 minutes. Let it cool on a wire rack before slicing.
The manufacturer notes that the bread can also be baked in a bread machine by following the machine's own instructions. Store the unopened sachet in a cool, dry place.