Pearling is a milling process that removes the tough outer hull and some or all of the bran layer from a whole grain, leaving a smaller, rounded, polished kernel. It is most commonly applied to barley, producing pearl barley, but is also used on wheat, farro, and sorghum.
The technique relies on grain-milling equipment that tumbles the grain against an abrasive surface to strip away the fibrous hull, a step originally needed simply to make the grain edible and faster-cooking. Modern pearling mills use a rotating abrasive drum or grinding wheel; the longer a batch of grain stays in the machine, the more bran is removed and the more polished, or "pearled," the grain becomes.
Pearling is valued in the kitchen mainly for what it removes rather than what it adds. Stripping the hull and bran shortens cooking time considerably compared to the whole grain form, softens the texture, and extends shelf life, since the oil-rich bran is what causes whole grains to turn rancid. This makes pearled grains a practical choice for soups, stews, pilafs, and grain salads where a quicker-cooking, tender bite is wanted.
Because pearling removes bran and some germ, pearled grains lose fiber and some nutrients compared to their whole-grain counterparts, similar to the difference between brown and white rice. Partially pearled grains, sometimes labeled "lightly pearled" or "semi-pearled," retain more bran and nutrition while still cooking faster than the unprocessed grain.
Pearling should not be confused with simply hulling a grain: hulling removes only the inedible outer husk, while pearling continues past that point to abrade away the bran as well, which is why pearled grains look smoother and lighter in color than merely hulled ones.