I am new to sourdough baking and a week ago was given some starter by a friend. I put it in the fridge and fed it a tablespoon of brown wheat flour and a little water and then put it back in the fridge with the lid on the jar. Some days later I noticed that the flour and water had seperated. I mixed them, added a little more flour and water and put them back in the fridge. They seperated again. Last night I took the starter out of the fridge and added more flour and water but it has seperated again. On the watery surface there are a few very round globules of floury goo, the smell is quite sour but the colour is creamy/yellow and I can't see any mould. Is it ok, what shall I do if I want to begin baking with it? Do I need to throw it away and get some more?