100g bread flour (e.g. wheat, spelt, kamut or rye).
100g (3/4 cup) filtered or spring water
1 litre (1 quart) capacity glass jar, sterilised
paper towel or several layers of cheesecloth
rubber band
Instructions
Combine the flour and water in the glass jar and stir until well combined and no dry flour lumps. The resulting mixture will look sticky and be thick like glue. Scrape down the sides of container as much as possible and cover with paper towel and the rubber band.
Place the container in a warm area and let sit for 24-48 hours. After this time proceed with your first feeding (coming tomorrow)
Recipe by @OmNomAlly at https://omnomally.com/2014/07/20/making-a-sourdough-starter-day-1/