So i know there are many ways to ruin good head:) beer head that is. I have a helles and have noted a slight Diacetyl when it gets to room temp. I had good head for a few weeks and have recently noticed that it has disappeared completely:( I did not do a protein rest when brewed single infusion temp of 150. Pilsner, munich and melanoiden used wyeast 2308. Did a proper diacetyle rest and still dont know why i have this character but thats another post i suppose. Only thing i can think of is i have not cleaned my bear lines in 6 months and when i do i clean them with PBW. Any suggestions.