Bergamot is a type of fragrant but sour orange. Actually it is a hybrid (most citrus fruits are) between a lemon and a sour orange (which itself is a hybrid between the pomelo and the mandarin). Mostly bergamots are grown in the southern part of Calabria where they first appeared in the 17th century. The juice while sour, lacks the characteristic bergamot flavour. The zest is included for this reason although it can be intense if too much is added. Add sparingly and taste before adding more to ensure you are happy with the amount.