I used pearled barley in this recipe because it's what is found in most grocery stores. However, you can use hulled barley instead and increase your PC time to 20 minutes. Hulled barley is considered a whole grain, while pearled barley is not. Pearled barley has the outer shell (hull) removed and oftentimes another layer called the endosperm. Hulled barley only has the hull removed and is considered slightly more nutritious. Hulled barley will not absorb as much liquid, so you may want to start out with only 4 cups of beef stock or broth instead of 6.