Why Einspänner Coffee Drinks Are Everywhere | Eater
"The global chain popularized 'cold foam' after first adding it temporarily in 2014 and later making it a permanent, multi-flavored menu element; its mainstream rollout helped normalize foam-topped beverages, fueled a culture of hyper-customized orders, and generated heavy demand (and recurring gripes) among baristas." - Bettina Makalintal
