Originally Posted by audger
its impossible to know this without lab testing.
Perhaps, however, level of bitterness, sharpness and hop aroma/flavor are all perceived on the pallet. For a test batch I ran through a recipe I am very familiar with and noted significantly more bitterness than I had experienced before by using bags when tasting the wort during the boil. So for non-lab quantification I was very satisfied with my hop utilization. This is with the only variant in the recipe being the usage of this screen filter as opposed to hop bags.