I love millennial scientists.
As much as I desperately want revolutionary battery life and cures for diseases, it’s always great when an experiment comes from a bar and Starbucks.
For Emilie Dressaire, assistant professor of mechanical and aerospace engineering at the New York University Polytechnic School of Engineering, inspiration came in the form of a latte, and for Alban Sauret, researcher at the French National Center for Scientific Research, it was a Guinness.
Both, along with several colleagues, had noticed and were intrigued by the damping effect foam has on beverages and how that facilitates carrying them.
In a paper recently published by the American Institute of Physics and co-authored by François Boulogne, these researchers discovered that foam (from your latte or a stout) minimizes sloshing. By carefully adding one layer of foam at a time, they saw that five layers of foam (15mL or 3 teaspoons) correlated with less movement from the liquid beneath it by tenfold.
More foam didn’t have a significant effect on the liquid sloshing, nor did foam in the middle of the glass. The foam clinging to the sides of the glass are what dampens sharp movements from the liquid.
While this has larger implications for the way we transport substances like fuel, we’re more concerned with not spilling hot coffee all over ourselves and not looking like sloppy drunks on our
third sixth eighth beer.