This is the first time I have actually needed a blow-off assembly for my carboy. it is a 7gal and i have 5 gal of Northern Brewer's Australian Sparkling Ale going in it. i don't know what happened but it took off like a shot.
I made a starter with Thames Valley yeast and pitched at the right temps.
I am wondering if the late Pilsner LME addition was the culprit of the blow off. Here is the picture and i did not get a blow off brewkake