The difference between Tequila and Mezcal

Mezcal is a word in Nahuatl that means 'oven-cooked agave'. The agave or maguey is a sacred plant that has been venerated in many Mexican indigenous cultures for centuries. There are over 200 different types of agave and over 30 of these are used in the production of mezcal, the most common one being the 'espadin' (Agave angustifolia). Mezcal is recognized as designation of origin and can only be produced in some municipalities in the states of Durango, Guerrero, Oaxaca, San Luis Potosí, Zacatecas, Guanajuato, Tamaulipas and Michoacan. The diversity of agaves accounts also for the varieties of flavors and aromas found in the different types of mezcal. Its popularity has been increasing in the last 10 years with several 'mezcalerias' opening in big cities like Madrid, New York, Paris, and London.

Tequila is a type of mezcal that can only be made from one species of agave: the 'blue agave' (Agave tequilana). The drink is original from the region of Tequila, in the state of Jalisco, but today its denomination of origin covers also some municipalities of the states of Guanajuato, Michoacan, Nayarit, and Tamaulipas. Depending on the region where the blue agave is grown, the tequila produced will have different sweetness and odors. There are 4 categories of tequila: Silver or White Tequila with little or no aging, used primarily to make margaritas. Gold Tequila that is unaged silver tequila colored with caramel. Reposado Tequila is aged in wooden tanks for at least two months. And Añejo Tequila that is aged in wooden barrels for at least 12 months. 

Other less known, but also very tasteful distilled beverages are Bacanora and Sotol. These are produced in Sonora and Chihuahua respectively and are mostly artisanal productions. Bacanora is also made from Agave angustifolia, while sotol is made from the sap ofDasylirion wheeleri, a yucca plant.


Regions with denomination of origin for Tequila, Mezcal and Bacanora



The distillation process of these beverages is pretty much similar. Blue agaves reach maturity within 8 – 10 years and start growing a flower stalk, which is intentionally removed by the jimador. These plants only flower once in their lifetime and removing their sexual organ redirects the plant growth to the central stalk. Since the plant has no more reason to invest its energy in sexual reproduction, its starts storing its pulp and swelling up. Once the plant has a considerable size, the leaves are removed and only theheart or piña, which stores the majority of the fructose, is processed.

For mezcal, the piña is cooked underground with firewood, which gives its distinctive smoky taste. Then it is crushed with a stone wheel pulled by a mule and shredded to extract the aguamiel. For the tequila, the piña is cut into pieces and baked in pressure cookers until the starch is converted to sugars. Fermentation determines the purity of the final product. A 100% pure tequila or mezcal will have only agave juice and water. Mixed types will contain up to 40% alcohol derived from other sources, usually cane sugar.

Mezcal and the worm

Some people relate the famous gusano de maguey to mezcal and even swear by its hallucinogenic and aphrodisiac properties. The worms might alter slightly the taste of the beverage but the real reason to why bottles of mezcal have one is just for marketing purposes. However, when cooked and seasoned with the right ingredients this pest is considered a delicacy, half a pound can be sold for up to $50 USD!

How do we capture bats?

To capture bats we set up mist nets made of very thin nylon thread that the bats only detect when they are too close and get tangled. This fine mesh is very soft and does not harm them in any way. We remove the bats out of the net making sure they do not get any more entangled. To do this, first we look for the direction in which the animal flew into it. The last body parts to come in contact with the net are the feet and back. We look for these and hold them tight without squeezing the bat and making sure it does not bite us. We gently pull it away from the net and we begin to release the rest of the body. The thread is pushed up its head and removed as if we were taking off a T-shirt, the wings are the last part to come out.

Some nights when the bat activity is at its peak or if we are near a roosting site, more than one bat is captured at the same time. As soon as we release one animal we put it in a fabric bag and continue to release the rest of the other bats that may have been caught. We have to be very efficient and organized, some nights we can capture up to 100 individuals! While some people are taking out bats from the nets others record body measurements and collect samples.

I collect tissue samples from the wings. I use a biopsy punch to take small circles of skin of about 3 mm in diameter. These holes are so little that they do not affect the bat's ability to fly. In nature, bats injure their wings with tree branches or spines but these injuries heal quickly usually within 2-3 weeks. Bats are commonly captured with holes in their wings that are much larger than those inflicted by wing punching.

Apart from skin, we sometimes collect other samples that are useful for other researchers (e.g feces, urine, parasites, pollen). We also take measurements of the forearm length and the overall size of the body to determine their life stage ( adult or juvenile). We weight them, determine their sex, and their reproductive status. For example, pregnant females have a round and swollen abdomen that if touched gently the fetus wings can be felt! Lactating females have a nipple under each wing, close to the armpit, that drips milk. Males during the reproductive season have swollen testicles. All this information is important to keep track of the timing of reproduction during the year. The samples are stored in a special liquid or in alcohol at -20°C to keep nucleic acids stable before DNA is extracted in the lab.

After we have finished collecting samples and taking measurements we release the bats back to their habitat!