Top of my sourdough starter has gone grey I started my first sourdough starter about three weeks ago and after one week put it in refrigerator and the next week fed if 3 times in 12hours intervals an then put it back into fridge , but now there is some greyness on its surface which seems part of the starter itself and is not like fungal mould but i'm worried if it's safe to use or not ?
Gray discoloration is normal and nothing to worry about. If you see orange or pink then your starter should be thrown away.