Cristina Spanò In late 2016, the Swedish company Oatly set up production in North America and began shopping its oat-derived “milk” to New York City’s latte cognoscenti. By the next autumn, oat milk had conquered the city’s “most esteemed coffee bars” at a “practically unheard of” rate, according to the coffee trade magazine Sprudge. Chic cafés peddling a grainy Scandinavian-inspired formula may sound too twee for words.