Caution — drunkards. My favourite warning sign on the roads*. The source of their booze, the maguey plant, is on the left. Photo: Libertad Sanchez-Presa.

Once you leave the main roads and cities, a large amount of Mexican culture revolves around the Agave. Its most internationally renowned member is the blue agave, Agave tequilana, whose sugary heart is used to make tequila. A less well-known drink is mezcal, which can be made from a range of Agave species, and by small producers. This allows for a wide variety of styles and flavours, making it a more diverse and interesting drink than mass-market tequila.

In the region where we’ve been working, however, the dominant species is Agave americana, known as maguey. The plants are everywhere, either as dedicated plantations, scattered among crops, or surrounding houses and smallholdings. They’re not just a weed though; they are carefully tended and visited regularly to harvest the sugary sap from their core, known as aguamiel (honey water).

The heart of the maguey plant contains a pool of sugary sap (aguamiel). In this case it is protected from evaporation and contamination by a plug of igneous rock.

During our hunt for the lost firs, which was a great adventure, we ended up walking through a number of farms in the foothills. In one we met a local woman collecting her aguamiel, who showed us how it was done. The process is pretty simple: a coke bottle with a hole in the bottom and a tube attached is used to suck the liquid straight out of the core, then drained into a bucket. She then scrapes out any scum or accretions on the bottom of the core, which ensures that the plant continues to secrete more sap through what is effectively an open wound. Most of her teeth were missing, which can probably be attributed to a lifetime of doing this.

A local farmer near Metapec sucks the sap from the heart of a maguey plant using an improvised bottle with a tube attached.

She offered me some and, being generally willing to try everything, I naturally obliged. It’s sweet with a distinctive flavour, in this case enhanced by a number of dead flies which added an interesting mouth feel.

In some places you can buy the aguamiel pure, though one imagines they filter it first. Its most important value, however, is to be fermented into the mildly alcoholic** beverage pulque. As you drive through rural areas there are occasional improvised signs next to shacks declaring its availability. Pulque is sold by the litre***, dispensed into whatever container you have to hand. We’ve been using old plastic water bottles, though this makes them impossible to ever use for water again because the pulque leaves a lasting unpleasant odour in the bottle.

It’s best drunk fresh because it continues to ferment in the bottle, which shouldn’t be closed too tightly as the build-up of gas can cause it to explode, especially if you’re bumping along dirt roads as we tend to be. Left for too long it becomes viscous and unpleasant.

The drink is the favoured end-of-day beverage for labourers, serving the role that beer plays elsewhere in the world. It’s slightly sweet, frothy and refreshing. We’ve tried a number of pulque shacks and experienced the full range of quality. Some was delicious and moreish, another so bad that one sip had us spitting it out and feeling queasy for the rest of the day. We’ve been going for pulque natural, the pure version, although in many places you can buy it flavoured with fruit juices.

Pulque is also used to make the dish barbacoa, a speciality of the State of Higalgo, which is meat (usually pork) soaked in pulque, wrapped in maguey leaves and baked. The result is something like pulled pork; tender and juicy with a characteristic flavour. It can then be wrapped in a taco with the usual accompanying relishes.

Is there a potential mass market for pulque? Personally I doubt it. Achieving greater quality control and consistency would not be impossible, but the difficulties of transporting it and keeping it fresh mean it’s unlikely to supplant beer. In the villages and rural parts of the country, however, it remains an important part of daily life. It’s also a great way to finish a long, tiring day of fieldwork in the forest.

* Not, I should add, an official Mexican highways sign. Someone had stuck their own sign on top of the existing one. Drunkards of Mexico, we salute you.

** I sank a litre of it by myself a few nights ago. It didn’t get me anywhere even close to drunk but it did give me a vicious hangover. I won’t be trying that again.

*** We’ve paid 10–12 pesos per litre, which is around 50 pence.