For years on end I passed a Pulqueria signed
"El Higado No Existe (The Liver Does Not Exist)"
On Mex 57 in the early summer you may find young men standing on the shoulder of the highway selling "pulque" before it has a chance to ferment.
It is called Agua Miel and it is delicious. Finding fresh pulque, young and sweet is not the easiest task as supplies are limited and customers have spoken for the next batch. Pulque that goes on to be a week old can be quite sour.
If a miracle happens and you find yourself surrounded by Mexican friends drinking pulque it is customary to slop a bit on the floor to honor the pulque god -- 400 rabbit.
Another fermented drink is Tuba. It is found mainly on the coast where there are lots of palms. Tuba is fermented palm sap. It is customary to have a handful of peanuts tossed into the Tuba. Tuba is more potent than Pulque about the same as wine. Caution should be used if you're driving.
I will neglect to mention Sotol, fermented pine sap.