Why did my Guinness turn into a solid?

Question

On St Patricks day I was having a Guinness. I also had a bottle of Baileys. Clearly somewhat inebriated I thought mixing some Baileys into my Guinness would surely create a remarkable sweet chocolate flavor. Instead, basically half the beer turned into a solid. I assume… it must have curdled? Why? How? What?

In: 598

Answer 1

We used to drop a shot of baileys into a pint then race to drink it before it curdled. Called it an Irish car bomb.