This starter is 6 days old. As you see, it has a quite grey surface on top. My recipe for this starter is simple, just same amount of flour and water and fresh the starter once a day. I tried the same recipe many times , but all the starters had same looking. Does this grey surface mean that my starter has a problem ?
When stired up , the starter looks like above.
Here is another question. After being freshed, the starter begins bubbling up until it becomes double in size. I guess it takes about 5 ~ 6 hours and stays there for another several hours then, starts falling down. Should I feed the starter when it shrinks back to the original size or wait for and keep the next feeding time? ( I have been feeding once a day .)