I made a flan, added lime zest and grated ginger, and it was a flop. What is happening? I tried cooking it an extra few minutes, but the flan was runny and looked a bit like scrambled eggs.  I have tried this before, and it worked.  this time, I added more lime zest and ginger root for a more flavorful dish.  Was it the lime zest?  Was it the ginger root (freshly grated)?  What might have been going on?  how do I avoid the problem in the future.

Thanks very much!
Sounds like a classic case of too much acid or putting in your acidic ingredients at the wrong times. If you haven't already, try adding your lime zest to your water and sugar at the beginning and the ginger to the warmed milk.