Calamansi

Calamansi (the calamondin) is the Philippines' all-purpose citrus: a small, round, thin-skinned fruit, no bigger than a large marble, that ripens from deep green to orange while its flesh stays vividly orange. The juice is fiercely sour — sharper than a lime — yet carries a sweet, almost mandarin-and-orange-blossom perfume that sets it apart from other acid citrus. Squeezed over grilled meats, noodles and soups, stirred into soy sauce or fish sauce as a dipping condiment, and pressed into the ubiquitous chilled calamansi juice, it is the single sour note woven through nearly every Filipino table.