So I started a batch of special bitter last Friday. It's in a plastic bucket so the airlock has been my only visual clue to what's going on. By the middle of this week, the airlock was only bubbling about once a minute. Last night I opened the bucket to get some brew out to take a gravity reading (I was planning to leave it for at least another week but wanted to get a sense of what was happening). I was surprised to see that there is still a substantial krauesen layer and lots of crud still in suspension. Obviously, I closed it back up and plan to let it sit for a lot longer. Is it normal for there to be that much krauesen after a week? I thought the primary fermentation would largely be done by now. I planned to leave it in the fermenter for conditioning anyway, but just want to make sure that there is nothing else I should be doing.