Pearl barley is not the same as whole grain barley. Following is an explanation of the difference between whole grain barleys—such as hulless barley and hulled barley—and pearl barley.
Like many of its fellow grains, the barley grain contains an outermost hull that is not considered digestible. For this reason, the outermost hull must be removed from the grain, and this removal requires some processing.
There is a special variety of barley available in some natural foods stores called "hulless barley." In this variety, the outer hull is so loosely attached to the grain that very little processing (if any at all) is needed to remove it.
From a nutritional standpoint, however, hulless barley is not essential, because few nutrients are lost with removal of the hull alone. Hulled barley and hulless barley would both be considered whole grain barley, and both make good choices from a nutritional standpoint.
Pearl barley takes the processing procedure one step further. With pearl barley, not only has the hull been removed, but the remaining grain has also been polished or "pearled" to some degree. The amount of polishing may vary significantly, however. In general, barley is increasingly polished (and increasingly robbed of nutrients) when you move down the line from regular to medium to fine to baby pearled barley.
An interesting category of barley that lies in between hulled and pearled barley (both from a processing and a nutritional standpoint) is pot barley, also sometimes called scotch barley. In this form of barley, the hull has been polished off, but the polishing process isn't taken much further, leaving most of the remaining grain intact. Although not as fully whole grain as hulled barley, pot barley is still a better source of nutrients than pearled barley and a good nutritional choice.
One final note: in some natural food stores, you will also see "hulled barley" referred to as "dehulled barley."
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