Sourdough Starter Day 4

After I showered this morning, I checked the sourdough starter.  It had separated again overnight and smelled too.  Not sure if it's supposed to do that or not?  Probably not .. but I'm going to be patient and complete this.  I don't want to stop too soon and then not succeed where I could have if I had only waited..
So on we go.

Here's a picture of how it looked this morning before I did anything to it.

I stirred it up, and then I completed Day 4 instructions.

Day 4: add 1 1/2 oz flour and 1 oz water

Now, that's what I did, but what the directions from this blog said was actually 1 oz flour and 1/2 oz water.  So I remembered wrong.  I have no idea what affect that will have on the starter.  As the blog said, today was fixing the hydration to 100% hydration, meaning equal parts flour and water are in the mixture now.  By my calculations I have a total of 3 oz of flour and 3 oz of water.  This means that I've added 1/2 oz more of each flour and water than she did at this point.  I think that will be ok.  The point is that I have reached 100%hydration.

Here's what it looks like.  It's thicker now, and it coats the spoon.

I'm still concerned with the smell.  Not sure what it's supposed to smell like.  I am probably not stirring it often enough, and I should probably stir instead of swirl to get more air in the mix. She did say that air was an important ingredient. She also said it should smell like buttermilk.  Does anyone know what buttermilk smells like? I don't buy or use that often, so I have no idea.  Perhaps I should go buy a quart so I know what it smells like?

What do you think?