How we tested
Capers are one of the test kitchen's favorite stealthy ingredients. Both salty and lightly acidic, these small buds make the butter and lemon sing in chicken piccata and highlight the nutty, sweet garlic flavor in pasta puttanesca. Once opened, a jar of capers can last in the refrigerator for months, which makes them a convenient ingredient for weeknight cooking. We often stir whole capers into dishes or sprinkle a handful over a finished dish. Although they're most closely associated with Mediterranean cuisine, they're used in other culinary traditions, too. Capers appear in English cookbooks from as far back as the 17th century.
Most American supermarkets sell capers in multiple styles and sizes. Capers packed in salt are especially tender and often have a wider range of delicate flavors, but they must be repeatedly rinsed before use, and their nuanced flavors are easily overshadowed in recipes. For everyday cooking, we like the convenience of brined capers. In previous tastings, we also determined that we prefer a small size known as nonpareil. To find out which brined nonpareil caper is best, we purchased six products and sampled them plain and cooked in our Chicken Piccata.
The Challenge of Cultivating Capers
These tiny green spheres are actually flower buds harvested from a spiny shrub (Capparis spinosa) that thrives in the hot, dry climate of countries such as Italy, Turkey, and Spain. If left on the bush, the germinated flowers grow into caper berries. When pickled, they're edible, too, but their large size and crunchy seeds make them better suited for an antipasto plate than for cooking.
The flowering process happens quickly and repeatedly. All the buds are hand-picked and then sorted by size with sieves or screens. After they're harvested, more buds appear, which are ready for harvest in 10 to 12 days.
However, capers are notoriously difficult to cultivate. As a result, most capers—even those harvested for commercial processing—are wild. “The caper industry is still in its infancy,” explained Brian Noone, a horticulturist and the author of the book Capers: From Wild Harvest to Gourmet Food (2016). Having spent the past two decades attempting to cultivate capers, he's well aware of the challenges. Noone told us that only about 30 to 40 percent of caper bushes grown from seed “produce a decent harvest,” meaning one bush might yield 2 pounds in a single harvest while another might produce just 2 ounces. On top of that unpredictability, capers are difficult to harvest; the bushes grow low to the ground, sprawl out in lots of narrow shoots, and often have painful thorns.
What Do Capers Taste Like?
You wouldn't want to eat an unpickled caper. They're distantly related to the cabbage plant and have a bitter, radish-like flavor. To make them palatable, the capers are packed in salt or submerged in a liquid brine for 20 to 25 days. About halfway through this time period, some manufacturers drain and rinse the capers and place them in a new batch of brine. While stored in the brine, the capers ferment, which softens their texture and changes their cabbagey flavor to something more floral and mild. The capers can then be packaged in the liquid they're fermented in (usually slightly diluted with water) or in a fresh batch of brine. Often vinegar or another preservative is added during packaging.
All the products in our lineup contain capers, salt, and water plus a preservative in the form of vinegar, citric acid, or acetic acid. We can recommend every product we tasted, although we liked some more than others.
Our panelists quibbled about two things: One product was slightly musty, and another tasted a bit too strongly of vinegar. The rest tasted just as capers should: “bright,” with “a nice ocean-y flavor” and even “floral” notes. In chicken piccata, our favorite capers added a “briny” flavor to the sauce without making it too salty.
The Size and Texture of Capers
All the capers in our lineup varied slightly in size; some were about the size of a pea, while others were smaller, like uncooked dried lentils. One product had a considerable number of these tiny capers. Although the littlest capers were harder to scoop up with our forks, most tasters didn't object. We did have opinions about texture in general, though. Some capers had started to unfurl, like roses losing their petals, and these felt a little “soft” and even “mushy.” Our favorites were firm, with tightly packed leaves and “a satisfying crunch.”
Which Factors Matter?
It's hard to pinpoint the exact reason for the differences in the capers' flavor and texture. However, the time and day of the harvest matters. Capers are tightest in the early morning and generally at the end of the summer, so softer capers may have been picked at the end of the day and/or at the beginning of the summer. Prolonged fermentation can also soften them. The variation in size is probably explained by the lack of sophisticated harvesting equipment. Sorting is still done by hand, using sieves and screens, and is an imprecise process.
But even those small textural variations can affect how we perceive flavor—especially sodium. According to their nutritional labels, the products in our lineup contained from 106 to 127 grams of sodium per teaspoon, but those numbers didn't track with our tasters' impressions. According to our science research editor, it's possible that the water retained in the softest capers diluted the taste of the salt; some of our tasters found them “bland.” And because firmer capers contained less water, we may have tasted their salt more, which we liked. Smaller capers, which have more surface area per teaspoon, also taste more intensely salty. As for the mild mustiness we noticed in one product, it's possible that the brine was to blame. Although manufacturers may strain and dilute the original brine, some research shows that capers in older brine are more likely to exhibit off-flavors.
The Winner: Reese Non Pareil Capers
After calculating the results of our two blind tastings and learning more about how capers are grown and harvested, we're more sure than ever that these little buds deserve a place in your kitchen. They boosted the flavor of the lemon and garlic in chicken piccata, and tasters loved their crunch. In a pinch, any product we tasted will do. But we recommend seeking out our winner, Reese Non Pareil Capers. They had a pleasantly firm texture and were “salty” and “tangy” but didn't overwhelm the chicken piccata. As one taster summed it up, they're “just what I want in a caper.”
We evaluated six brined nonpareil caper products. Panels of 21 America's Test Kitchen staffers sampled the capers in two blind tastings: plain and in our Chicken Piccata. Scores were averaged. Ingredients and sodium levels were obtained from product packaging. Where necessary, serving sizes were converted to 5 grams or about 1 teaspoon. Prices were paid in Boston-area supermarkets and online. Products appear below in order of preference.