How to Make Sourdough Starter:

1. Day 1: In a medium-sized clear glass jar or Pyrex liquid measuring cup, mix together 25 grams all-purpose flour, 25 grams whole wheat flour and 50 grams water using a small wooden spoon (or wooden chopstick). Mix well to fully combine so that there are no dry flour particles visible. Cover with a lid or plastic cling wrap, and leave it at room temperature (70-80 F). Using a clear, glass container helps monitor the starter's progress (so you can see whether it is bubbling and rising). An ideal size jar to choose is one where the initial mixture on Day 1 covers no more than 1/5 of its volume capacity.
2. Day 2: After the first 24 hours, you will most likely see no activity. Any sign of tiny bubbling is good because it shows the mixture is alive, but it could take up to 3 full days to see any bubbling.
3. Day 3: Discard HALF of the starter and add the same ratio of flour and water (25 grams all-purpose flour, 25 grams whole wheat flour and 50 grams water). Stir well to combine and mark the starting level of mixture with an elastic band. Cover with a lid or plastic cling wrap again and allow the mixture to sit at room temperature (70-80 F) for another 24 hours.
4. Day 4: Discard all but 100 grams (about 1/2 cup) of starter and then add 25 grams all-purpose flour, 25 grams whole wheat flour and 50 grams water. Feed the starter this way, TWICE a day, roughly 12 hours apart (feed once in the morning and once in the evening). You might start to see a more predictable rising and falling with lots of bubbles.
5. Day 5: Repeat the steps taken on Day 4 (discard all but 100 grams of starter, and feed the starter twice a day, roughly 12 hours apart, with 25 grams all-purpose flour, 25 grams whole wheat flour, and 50 grams of water each time). At this point, the starter should definitely look lively with bubbling, and rise almost double in size.
6. Day 6: Feed one last time following the same method (discard all but 100 grams of starter and add 25 grams all-purpose flour, 25 grams whole wheat flour, and 50 grams of water). Place a rubber band around the jar to mark the starting level so you can monitor the rate of rise to see whether it doubles in size. The starter should hopefully double in volume within 4-6 hours of feeding with lots of bubbles throughout and on the surface.

How to Check if Starter is Ready:

1. To check if the starter is ready, you must do the float test.  Place a teaspoon of starter in a glass full of water. If it floats, then it’s ready to be used to make sourdough bread. If it does not float, then continue to feed your starter for one or two more days on the same feeding schedule (twice a day, roughly 12 hours apart) and do the float test whenever you feel that it is ready. 

How to Maintain and Use your Starter

1. To keep your starter healthy and lively, store it in the refrigerator with a cover and feed it regularly.
2. Feed your starter at least once a week by discarding HALF of your old starter and adding 25 grams all-purpose flour, 25 grams whole wheat flour and 50 grams water each week. Remember to save at least 30 grams (about 3 tablespoons) for next use.
3. To use the starter to bake sourdough bread, take it out of the refrigerator 6 to 12 hours in advance and discard HALF of the old starter and feed it the same way (25 grams all-purpose flour, 25 grams whole wheat flour, and 50 grams water). Let it rise for 6 hours or until doubled in size. The best time to start your sourdough preparation is when your starter doubles in size at its peak after feeding. This could take 6 to 12 hours depending on room conditions and the type of flour used.