I love a good Guinness. wait that would imply there is a bad Guinness, which there isn't. So I love a Guinness. I like the angle of your shot here. The foam or flash reflection at the bottom of the frame is a big distraction though.
I love beer and Guinness I must resist giving a 10........ sorry a solid 6.5 and I have to round down on this one. Still I bet it bests my entry.
Cheers
Either out of focus or needs sharpening... The glare on the lower part of the glass is distracting. I do like your choice of background and overall composition.
The glare on the glass is very distracting, maybe a tighter crop from the bottom? Also the top part and the foam seems out of focus and it's not really appearing black and white on my screen, more rust and white. A 3