This picture contains two extract batches made on two successive days approximately two weeks ago.
One is a Honey Weizen (OG=1.048; Wyeast 1010 American Wheat Yeast), and the other is a Phat Tyre (OG=1.052; Wyeast 1762 Belgian Abbey I), both from Northern Brewer.
The instructions for both of these say to do 1-2 weeks in primary and 2-4 weeks in secondary. What I have usually done when I see this instruction is to leave it in primary for 4 weeks and then bottle.
The Honey Weizen still has a krausen. The Phat Tyre's krausen has dissipated. (To be honest it could possibly be the other way around, I forgot to put a post-it on each container ... I will know with certainty which batch is which when I disconnect the temperature probes (those black cords you see in the picture) from my Raspberry Pi, as per my temperature monitoring, and I'll edit this if I was wrong)
A) What is the reason for dissipation or non-dissipation of krausen? I'm assuming it has to do with the yeast.
B) Does it matter if I bottle when the krausen has not dissipated?