If it was draft, was it on a nitro line? Did they bleed the line enough to get you fresh beer?
If it was a bottle or can, was it a widget can or bottle?
Yes, though it might take awhile. I found a draft can ( the one with the little nitrogen widget ) at the back of my fridge that had expired a couple of years ago. It was not drinkable. I was sad :(.
Is this a place that serves a lot of Guinness? If not, then it could certainly be old beer, which could taste off. If it is, then it’s possible they have a dirty line or something, which can also cause an off taste.
It would be fair to ask if they changed the keg between the two…maybe you got the end of the first keg and the start of a fresh one?
I often find I’ve gotten a bad Guinness. If I’ve downed six or seven of them, the seventh or eighth invariably makes me throw up. How they get away with this I’ll never know.
I am puzzled. IME, Guinness stout in the UK varies from batch to batch. Guinness served from a tap in the US tastes like dirty socks: I assume it has gone stale. Admittedly, I haven’t tried a Guinness in the US in years, so maybe that’s changed.
It could be a case of the … what do you call those cables it’s pumped through? We’ll call them cables. The cable system could need cleaning. Seriously.
It could also have been a bad barrel. When I worked in an irish pub it happened now and again. How did it taste? Was it sort of watery, with the head just dissapearing after a sort while? Did you tell the bartender about it?
I do know that if your bartender manipulates the pour to form a picture in the head, even if it is a shamrock, you are allowed (nay, encouraged) to stab him in the neck with a fork.
Dirty line is the first thing I thought of as well. There’s one pub in town that’s always the best place to get a Guinness because they keep their lines fastidiously clean. Most other places taste a little off.
But more seriously, canned Guinness is apparently supposed to be chilled. I’ll happily drink room temperature from a tap, but I’ve always stuck the cans in the fridge.
I’ve had lots of Brits tell me of the hazards of dirty lines. I was in one British pub here in Bangkok, owned and operated by an Englishman, with an English friend, and my friend ordered a pint of some ale he had been extolling the virtues of. When he tasted it, he made a sour face. Tasted all skunky. Had the owner taste it. The owner made a face and apologized. The line was the culprit turns out.