Most people who take a big juicy bite out of a lime will find that they are quite sour, though it does depend on the type of lime as well as the individual tasting it. For the most part limes are quite sour, mostly due to the fact that they are highly acidic and also because they contain lots of vitamin C.

The ascorbic acid which is found in limes contributes to the sour taste which you will no doubt experience when taking a bite out of one or drinking lime juice. Although there are certain fruits that are more acidic than limes, they still contain a significant amount.