Speaking of foam on beverages doing some spectacular science-y stuff — and not to be undone by beer — it looks like coffee-infused foam can remove lead and mercury from water. Stand back, science is happening and it's remarkable.
No Cuban meal is complete without a café cubano (Cuban coffee). A well-made café cubano has a thick layer of sweet crema (cream) floating over strong espresso. To get the crema right, whisk about 1 tablespoon of the espresso with sugar until it turns foam