Mystery of texture of Guinness beer: inclination angle of a pint glass is key to solution

A team of researchers from Osaka University and Kirin Holdings Company, Limited demonstrated that the texture-formation in a pint glass of Guinness beer is induced by flow of a bubble-free fluid film flowing down along the wall of the glass, a world first. This phenomenon is found to be analogous to roll waves commonly observed in water sliding downhill on a rainy day. Their research results were published in Scientific Reports.
Source: EurekaAlert,