Why does pouring beer onto the sides of the glass prevent it from foaming, as opposed to pouring it straight down the middle?

Question

Why does pouring beer onto the sides of the glass prevent it from foaming, as opposed to pouring it straight down the middle?

In: 83

Answer 1

The foam in beer is a lot like the bubbles in soda. It stays dissolved when the beer is under pressure in the can/bottle/keg, but comes out as foam when the beer is poured.

And just like with soda, it comes out faster if the beer is agitated. (For example, if you shake the can before opening, it’ll spray you in the face.)

When you pour beer straight down the middle of the glass it has more time to fall and hits the bottom of the glass harder. When you pour down the side of the glass it doesn’t hit the glass as hard.