Cold coffee with a tap injection of nitrous oxide sure sounds like a drug, but is a much tastier and cheaper way to get your kick on in the morning. Sumerian Coffee, on Shaanxi Bei Lu started serving this chilled coffee with a fizzy texture and distinctive taste since the beginning of March. The man of the place, Dave, says the brew “is the best invention in coffee serving since espresso was created” and you will most probably agree after having a cup of the liquid.