Day 1: combine 50 grams flour and 50 grams water in a glass container and stir very well. Leave in a warm place, out of direct sunlight, covered with a cloth.
Day 2- Feed your starter 50 grams flour and 50 grams water. This means, adding in a fresh 50g of flour and 50g of water and mixing it really well with yesterday's mix.
Day 3: Pour 50g of the starter into a fresh jar and feed it 50 grams flour and 50 grams water. (A ratio of 1:1:1.) Discard the rest.
Day 4: Pour 50g of the starter into a fresh jar and feed it 50 grams flour and 50 grams water. Discard the rest.
By day 3 and 4, your starter might be bubbling and have a slightly sour smell.
Day 5-10: each day pour 50g of the starter into a fresh jar and feed it 50 grams flour and 50 grams water. Discard the rest.
If your starter is doubling easily by day 6 or 7, within 6 hours of feeding, you can start feeding it 1:1:1 twice daily.
By day 10 it might be ready to use, though it could be earlier. Test it using the starter activeness test as written below.