My starter is of local organic small white grapes and bread flour. It's a couple years old.

In the last month or so, it has gone a bit "cheesy" and is slow to "activate".

Normally I feed with bread flour and hot water 1/.75 or so.  Then I put in the oven with the light on and it would usuually activate in an hour or so.

Took 8 hours to activate this time, and it wasn't like it has been.

Can this be fixed with some rye flour for a couple feeds and/or some OJ or cider?

The resultant bread is OK, but it lacks the rise of it's former self.

Now barly a half inch over the edge of the pan, when it was 1 to 1/12 inches over the top.