The Sourdough Project Day Four

Well, I had a change of plans, so I am making English Muffins instead of the bread. They fit into our menu better. I mixed my sponge last night. Sorry- there aren't any pictures. I was too tired. By last night the sourdough had completely stopped foaming, and had a yeasty slightly sour smell. I poured off what I needed for the sponge, and fed my sourdough with 1/2 cup water and 1/2 cup flour. Then I was surprised to see it start foaming again! What I am figuring out is that the yeast eats up all it can, so it stops foaming. Then when you feed the sourdough, it starts up again. Back to the sponge...The recipe says to let it sit for 2 to 24 hours and the longer the better. I'll make my muffins this afternoon, so it will sit about 16 hours.