Forget tequila and mezcal, Mexico’s oldest alcoholic drink is pulque, made from the fermented sap of an agave plant. The Aztecs dubbed it “drink of the gods” and reserved it for priests and nobles. Ancient murals depict the milky liquid fuelling grisly ritual sacrifice. After the Spanish arrived in the 1500s, pulque became widely available and the first pulquerías opened. It was the working man’s tipple and in the early 20th century there were more than 1,000 pulquerías in Mexico City.

In its natural state, pulque can be slimy and sour-tasting, but it is rich in probiotics, vitamins and minerals. Devotees believe it can cure everything from digestive disorders to diabetes.

By the 1950s, its popularity had plummeted, thanks in part to campaigns from beer and soft drinks companies. Now it’s in vogue once more, with old-school establishments being reinvented and neo-pulquerías popping up in the capital. One such venue is Pulquería Insurgentes in the city’s Roma district, a four-storey bar-cum-cultural centre that pulses to an eclectic mix of music, from ranchera to heavy metal and jazz.

Another bar in the Centro Histórico – Las Duelistas , founded in 1912 – has been transformed. Pulque is still scooped out of wooden barrels, but psychedelic murals adorn the walls, and hipsters outnumber old-timers. The drink is made in the age-old way: sap from the heart of the plant fermented for a week or two, then mixed and muddled with all manner of fruits, vegetables and grains – perhaps guava, celery or oatmeal – in a curado.

It’s Mexican heritage in a glass, and last night pulquerías were celebrating New Year’s Eve once more.

• This article has been amended as the main image originally showed the making of tejate instead of pulque.