The caper, a tiny pickled flower bud, is a widely used condiment whose history stretches back to ancient civilizations in the Mediterranean region. The unopened buds of the plant, known scientifically as Capparis spinosa, have been valued for their distinct, pungent flavor for millennia. This resilient perennial shrub is the source of both the familiar caper and the less common caperberry. Transforming the raw plant material into the salty, tangy condiment is a labor-intensive tradition that unlocks its complex flavor profile.
Defining the Caper Bush
The caper bush, Capparis spinosa, is a sprawling, spiny perennial shrub that is a native fixture across the Mediterranean Basin and parts of Asia. This plant is classified as a xerophyte, meaning it is specifically adapted to survive in arid or semi-arid climates with high temperatures and low water availability. It employs several mechanisms to reduce the impact of drought, including having thick, fleshy, and rounded leaves that help minimize water loss.
The shrub exhibits a remarkable ecological flexibility, often found growing in seemingly hostile conditions like rocky hillsides, cliff faces, stone walls, and even rock crevices. This ability to tolerate saline soils also classifies it as a halophyte, allowing it to flourish in coastal environments where other plants struggle. The caper bush produces attractive, showy flowers with four white to pinkish-white petals and numerous long, violet-colored stamens, though each flower typically lasts only about 16 hours.
The shrub’s physical structure consists of semi-prostrate, scrambling branches that can spread up to 10 feet wide, though it typically grows no taller than about three feet. Sharp, hooked spines develop at the base of each leaf petiole on many varieties. These spines present a challenge during the manual harvesting process.
From Bud to Condiment
The caper is the immature, unopened flower bud of the Capparis spinosa plant. The larger, olive-sized caperberry is the fruit that develops if the bud is left unpicked and allowed to flower. Transforming the raw bud into the tangy, edible caper requires a labor-intensive process, beginning with harvesting the small, delicate buds individually by hand in the early morning.
The harvested buds are spread out to wilt in a cool, dry place to reduce moisture content. This is followed by the curing process, which removes the buds’ natural bitterness and develops their characteristic flavor. Curing is achieved by covering the capers in coarse salt or submerging them in a brine solution of salt and water, a process that can take several weeks.
The curing causes an enzymatic reaction that releases glucocapparin, which converts into mustard oil and is responsible for the caper’s signature pungent and piquant flavor. Finished capers are graded based on size, with the smallest buds—known as Nonpareils, typically less than 7 millimeters in diameter—commanding the highest prices. Caperberries are also pickled, often in a vinegar solution, and are typically eaten like an olive or pickle.
Unique Nutritional Profile
Capers possess a unique phytochemical composition that contributes to their nutritional value, despite being consumed in small quantities as a seasoning. The buds are rich in polyphenols, compounds known for their antioxidant activity. The most prominent are the flavonoids Rutin and Quercetin, which neutralize harmful free radicals in the body.
The pickling and canning process plays a role in concentrating these compounds; studies indicate that curing may promote the conversion of Rutin into Quercetin. Canned capers contain high concentrations of Quercetin, sometimes exceeding 500 milligrams per 100 grams. These flavonoids are linked to various biological properties, including anti-inflammatory and antioxidant effects.
Capers are low in calories, protein, and fat, making them a flavor-dense addition to a diet. The notable nutritional factor is their high sodium content, a direct consequence of the salt or brine curing used to preserve and flavor the buds. It is recommended to rinse capers briefly before use to reduce the amount of added sodium.