I found a recipe on-line for sour dough bread where the starter is made over night and does not have to be replenished all the time. (This is not for me as I do not bake bread that often.) However, I have never tried the recipe as it calls for "corn flour" which, when I checked the internet, said that it is called corn starch in the UK. I doubt that this is what is meant in the recipe as I live in California. Can anyone tell me about corn flour and where it can be purchased?