Be gentle when removing the zest from any citrus fruit.

 

The fantastic zingy flavour is contained in the very fine coloured part on the outside only. 

 

Once you have grated the colour off, the white pith beneath is bitter and will spoil the flavour of your food. 

 

Use a sharp, fine grater and grate about three times then turn the fruit to a new spot.  This is all that is needed to remove the zest.