Butter tea, drunk in quantities and at a frequency that makes it a Tibetan obsession, is in fact a cornerstone of the Tea Horse Road. Tibet’s seventh century discovery of tea and demand for it launched the long supply journey (see story PU’ER TEA...THAT STARTED IT ALL), but the drink itself evolved very far from the way the southern Yunnanese—and the rest of China—drank it. Called po cha, bod ja or ja srub ma, and by the Chinese suyou cha (酥油茶), its preparation involves blending with yak butter and salt, and the result is a nutritious drink that very few people other than Tibetans care to drink. First, the tea must be boiled until thoroughly stewed, typically at least an hour. Then a chunk of butter (strictly speaking, this is dri butter, as yak is the male of the species) is put into a tall cylindrical churn like the one shown here, called a mdong mo, together with a handful of salt. The strong tea is added, and the mixture churned with a plunger. As British writer and explorer Spencer Chapman drily put it, “The result is a purplish liquid of unusual taste for tea, but as soup excellent’.” Tibetans drink this in considerable quantities and, as a notably hospitable people, always serve it to guests. Etiquette demands that each person’s tea bowl is constantly refilled after each sip, and so is never left empty. One of the more challenging aspects for non-Tibetans is that the butter is often rancid to some degree, a quality that the Tibetans themselves do not mind at all. The socially acceptable escape route is to leave the bowl untouched after your first sip (which is immediately topped up), and then, just before taking your leave, knock back the full cup. Honour and etiquette will have been preserved.