beer foam and metallic cups

[Chris Flagstad]

I was wondering if anyone else has experienced this phenomenon.
When I pour a beer into a metallic container (particularly the classic thrift store tankard), it gets really foamy. The head is also really dense with small bubbles, like those Guinness cans with the canister of nitrous in them.
Anybody know the science behind this?

[Graham Shearlaw]

Its quite simple, the inside of a tankard is quite rough and disturbs the drink more.
You can see this best with modern glasses, a new clean glass will have less bubble then an older one.
That's why there's often little nucleation points etched in the bottom of beer glasses for that little sting of bubbles.

And far more science then i care to repeat about the why, [url]Reddit: Why do bubbles in carbonated drinks or beers form from imperfections or scratches in glass? What causes them to form from surface imperfections vs randomly within the liquid?
[/url]https://www.reddit.com/r/askscience/com ... eers_form/

[Chris Flagstad]

Thanks!

So it's a reaction to the texture, not a reaction to metal?