Why does the “head” of foam when you pour a soda dissipate within a few seconds, but on many beers it lasts much longer?

Question

Why does the “head” of foam when you pour a soda dissipate within a few seconds, but on many beers it lasts much longer?

In: Chemistry

Answer 1

Beer’s protein content contributes to its foamy head by increasing surface tension. Unlike other carbonated drinks lacking protein, beer forms a distinct head due to this property. This phenomenon is akin to whipping egg whites, which also become foamy due to their protein content.

Additionally, some beers are nitrogenated rather than carbonated. Because nitrogen is less prone to escaping a liquid than carbon dioxide, the bubbles in nitrogenated beers, such as Guinness, are more persistent. This characteristic imparts the creamy texture and prolonged bubbliness characteristic of such brews.