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

To add to foaming prevention: rinsing out the glass beforehand will also prevent a lot of foam from being created. Otherwise the sides likely have some water scale/other imperfections that acts as a nucleation site (like coke and mentos)