Capers are the preserved, unopened flower buds of the thorny perennial shrub, Capparis spinosa, which flourishes across the sun-drenched landscapes of the Mediterranean region. These small, dark olive-green buds are renowned for imparting a distinct, briny, and tangy flavor to a wide variety of dishes. The intense flavor profile is not present in the fresh bud; it is a direct result of a post-harvest preservation process. The culinary ingredient must undergo a necessary curing step to develop its characteristic piquancy and become palatable.
Where and When to Harvest
The caper shrub naturally thrives in harsh, semi-arid environments, favoring hot, dry climates and well-drained, often stony or rocky soil. This resilience allows the plant to grow out of stone walls or along coastal cliffs in its native Mediterranean habitat. The harvest season typically spans from late spring through early autumn, aligning with the plant’s active growth cycle.
The caper itself is the tight, immature flower bud, which is the primary target for harvesting. If the bud is left unpicked, it will flower, and the resulting fruit is the elongated, olive-shaped caper berry, which is also edible after curing. The optimal time for picking buds is early in the morning, before the intense heat of the midday sun causes them to soften or begin opening.
Picking Techniques for Buds and Berries
Harvesting capers requires meticulous, repetitive hand-picking, which contributes to their market value. Harvesters must carefully pluck each unopened bud from the long pedicels that connect them to the stem. Since many wild shrubs bear small, curved thorns, the use of gloves and careful handling is often necessary.
The size of the caper bud is the primary determinant of quality, and buds are graded immediately upon collection. Smaller buds, often less than seven millimeters in diameter, are highly valued and known commercially as nonpareil. These smaller buds possess a more delicate texture and a less intense flavor than their larger counterparts. Daily harvesting is necessary during the peak season to capture the buds at their optimal size before they begin to open.
After picking, the buds must be handled gently to prevent bruising and ensure a quality cured product. The goal is to collect firm, tight, dark-green buds that show no sign of blossoming. Caper berries, the fully formed fruit, are also hand-picked when firm and immature, generally later in the season after the main bud harvest has subsided.
Curing Methods for Edible Capers
Freshly picked caper buds are intensely bitter and must be cured to activate the enzymatic reaction that releases signature flavor compounds, such as mustard oil. The two common methods for preservation and flavor development are salt curing and brine curing, each yielding a slightly different final product. Salt curing is a traditional method that results in a more concentrated, robust flavor profile.
Salt Curing
To salt-cure capers, the buds are first rinsed and thoroughly dried to remove excess surface moisture. They are then layered in a clean container with coarse, non-iodized sea salt, using a ratio that can be up to 40% of the capers’ weight. The salt draws moisture out of the buds through osmosis, creating a natural brine that settles at the bottom of the container.
The capers and salt mixture should be stirred or shaken daily for the first few weeks to ensure even distribution and uniform dehydration. The curing process typically lasts between two and four weeks. During this time, the accumulated liquid may be drained, and the capers can be repacked with a smaller amount of fresh salt. Once cured, the capers can be stored dry in the salt, which acts as the long-term preservative.
Brine Curing
Brine curing, or pickling, involves preserving the capers in a solution of water, salt, and vinegar, which often results in a milder, tangier flavor. This method is frequently preferred for the larger caper berries. A common preparation involves soaking the buds in plain water for several days, with daily water changes, to leach out some of the initial bitterness before they are submerged in the final brine solution.
The final brine is generally a mixture of white wine vinegar, water, and salt, sometimes with the addition of aromatic spices. The capers or caper berries are sealed in this liquid solution and allowed to cure for a minimum of a week. Regardless of the method used, both salt-cured and brine-cured capers must be rinsed well under cold water before use to remove the excess salt or pickling solution.