Or, how about Peruvian Morning Mystery Stout - Maybe it's infected, maybe it's not. Buy some for yourself to find out! But seriously of the two four packs that I have bought this year I have only had one that may even be considered suspicious. My palate was already fatigued at this point and it really just tasted uneven, like the coffee was fading and the bourbon/barrel characteristics were becoming more prominent. Not sour in an infected way, more of an alcohol twang.