Am considering brewing a lambic (likely using wyeast blend and some belgian beer dregs) have seen pictures online of the mould layer created on top of the brew in the carboy. How come this doesn't also happen in the bottle once bottled? Reason I ask is that a friend once tried to brew a cider using the wild yeasts in the apples (total disaster!) and I remember it had a thick mould layer in the carboy and after bottling mould grew on top of the liquid inside the bottles. Was quite disgusting but I've never seen this in store-bought lambics, can anyone explain why not? Do the bacteria die out eventually?
I dunno about commercial examples, but I've had small pellicles (not mold) on pretty much all of my sour/Brett beers in the bottle.
I have had pellicles in my bottles as well. Not the full on thick bubbly ones but a powdered sugar coating floating on top for sure.
The pellicle grows thicker in response to oxygen in the headspace. So while you might see a thin pellicle in the bottle, it generally won't be as thick as one you'd see in a carboy or especially a barrel.
When I bottled my lambics I got a thin pellicle on top, I 'riddled' the bottles (basically swirled them) three or four times a day apart. Pellicle broke up and settled out. Didn't bloom/gush on opening either.
