I brewed a lambic style ale and I pitched some wyeast 3278 lambic blend and some dregs from several other sour ales a few weeks ago. I have about 5.5 gallons in a 6 gallon glass carboy. It had strong fermentation for the first 2 weeks and has now left left the inside of the carboy head space completely covered in about 1/4 inch of krausen gunk and crud. It looks nasty and is so think I cannot see my beer and will not be able to tell if a pellicle forms? Will this crud that is completely coating the head space cause any off flavors or other issues or is it ok to leave it?
You should generally leave a lambic on the yeast from primary, it will be a food source for the bugs as it ages.
I do now that as the bugs will eat the dead yeast and help create more funk earthiness. I am just more worried about all the crud stuck to the glass in the headspace and if that could cause any unwanted effects.