It was a bit tricky to capture with our iPhone but what you’re looking at is the “pellicle” that forms on the surface of a sour-aged beer (it sorta looks like the surface of the moon). Shown is our “MAD MICHAEL” lagrrr! which has been sour aging for 4 months now. We had a taste and it is already pretty dang awesome, we expect to have it bottled in time for the Holidays – Rulpsen