The Hop-Go-Round simplifies the task of estimating bitterness. Unlike other methods, this takes into account the utilization rate, a critical factor ignored by simpler calculations. Once utilization has been determined, line it up with hop alpha acid content. Then, line up ounces against gallons and read the estimated IBUs. Equally useful for extract and all-grain brewers. Can you geek out on homebrew anymore than this? What a cool tool!