Kumquats are only a little larger than a grape. They are the only citrus fruit that is eaten completely whole – skin and all. In fact, the skin is the sweetest part. The first impression you’ll have of a kumquat is that it is sour – but that is only half of the truth. Once the tartness of the flesh and juice have faded, there is a mellow sweetness that comes from the chewy skin. Kumquats are strange yet satisfying little citrus fruits that can be found in our mixed boxes.