The HopBlocker offers a 95% efficiency on pellet hops and is virtually impervious to plugging! PLEASE NOTE: The HopBlocker is designed for use with pellet hops only. Whole/loose hops will plug the unit. While using whole hops, or a mix of whole and pellet hops, you must bag your whole hops in a large muslin grain bag. This will not affect the utilization rate and will result in significantly less wort loss.