I have made 3 different batches of beer, and carbonated them in a keg. They were carbonated about 4 psi higher than recommended. All three have come out without much of a head, and seemed a little flat. The funny thing is, that the grolsch bottles pop like a cork when I open them, so they seem to be under a decent amount pressure. I have bottle carbonated a bunch of beers in the past, and have never had a problem with a decent head or carbonation, which makes me believe that I at least brew the beer properly for it to do what it should. When I bottle it, I don't get a lot of foaming, so I am not loosing co2 at bottling time. The beer was in the keg under pressure for a week, so it should have an even co2 level. It almost seems that there is something going on like residue, but I go out of my way to be clean and sanitary. Any thoughts? Like I said though, when I open a bottle, it pops, and then pours flat.