NJ,
My observations with regards to peppers are, Green = bitter/savoury, Yellow = sweeter than green yet still has a slight bitter note, Red = sweet.
I could be wrong but doesn't the time of harvesting the pepper determine it's colour in a similar way to tomatoes? ie; Green = not ready, Yellow = all most there, Red = ready
In the Manchester area, you will often find all three in a Jalfrezi but only green in a Dupiaza or Bhuna.
Ray
