Why Does Beer Foam When You Tap the Bottle?

A swift strike on the bottle's mouth sends waves down through the liquid. The waves cause tiny bubbles in the beer to pulsate. ... The glass bottle may seem solid, but it can act like a spring, Rodriguez says. "So when you hit the spring, [the glass] compresses and creates waves.

Do you drink the foam from beer?

Foam, isn't the enemy: a heavy topping of bubbles doesn't damage the drinking experience—eventually those bubbles themselves fizzle into beer. So, get to pouring (and drinking!).

Is it better to drink beer from a bottle or glass?

Drinking beer straight from a bottle or a can is essentially cutting off your sense of smell and changes the way the beer tastes quite significantly. Compare that to drinking beer from a glass. Pouring your beer straight down into the glass activates the carbonation and creates a foamy head.