I am just starting to experiment with making bread and made my own yeast by mixing AP flour and water together and feeding it daily (twice daily at the beginning) per the Joy of Cooking instructions. It's been 2 weeks and I have what I think is a nice looking bowl of wild yeast - it's pretty fluid (not runny) and has lots of holes on the surface and it smells pretty "yeasty" I think. Whenever I feed it, it deflates and puffs right back up about 12 hours later.
I continue to feed it daily, but I'm not sure if
a) this is considered my "sponge" or "starter" (is this a poolish or a biga?
b) do i have to add commercial yeast when making a loaf if i use this yeast?
c) if i don't have to add more yeast, what is the typical ratio for substitution i.e., if a recipe calls for 1 tbsp of dry yeast, do i add 1 cup of my "wild yeast"?
Thanks for any advice you can provide. This site has been a tremendous help!