I've done about 6 all grain brews, and the 4 that I did without pilsner malt turned out great. I brewed Jamil's hefeweizen and NB's Lefse Blonde. They both came out not so good and had the same off flavor. I use proper sanitation practices, temperature control and pitching rates. My boil is the thing that I'm wondering about. I do a rolling boil but it's not super vigorous. It's uncovered for 90 minutes. The final turnout of these beers is very frustrating. Does anybody have any suggestions?