The distilling of Mezcal is surely one of the most fascinating activities related to spirits. Hard-bitten experts get shiny eyes when it comes to the old craftmansship of the mezcalero-families, which is passed from one generation to the next. Everything depends on carefully selected raw materials, experience and feeling.
First the agaves get slowly steam-cooked to turn the carbohydrates into convertible sugars. To do this a hole is dug in the earth, hardwood ignited inside and stones piled over and around it to hold the heat. When the wood has completely burned down and the stones are red hot, the hearts of the agaves get spread out on top of them. A layer of moist agave fibres protects the plants from the hot stone and keep it from burning.
The pile gets covered with another layer of dry fibres and finally buried under a thick layer of earth. It rests like this for 3 to 5 days to allow for a complete and slow conversion. After this steaming process the oven gets dismantled and the piñas are stored in a clean and dry place. The flesh of the plants is now soft, dark brown, and sweet-smelling from fresh plant sap and caramel. It has also acquired tones from wood, smoke and earth, all aspects of the process.
To prepare for the fermentation the plants are cut into pieces approximately the size of a hand, and unusable parts are discarded. The usable material is milled into a fibrous pulp (bagazo) by a stone mill (tahona, molino egipcio or molino chileno). The mill wheel stands upright in a shallow basin containing the agave pieces and is connected to a central pole by a horizontal beam. It is pushed in circles by a beast or machine.
The pulp produced by this molienda is now mashed in tanks of different types, depending on the region, its traditions and material availabilities: Dug-out trunks, stone pits and many more, but mostly big wooden vats. These containers are always open to allow for natural yeasts to begin fermentation. Cultivated yeasts are not used in producing traditional Mezcal. Depending on the size of the vat, outside temperature, humidity and the types of agaves the fermentation takes between 1 to 3 weeks. Its end is marked by decreasing sounds inside the vat, the shape of the openings in the pulp floating on top of the vat (both caused by the expulsion of CO2), the smell and temperature of the mash as well as the taste of samples taken on different levels of the container. When all sugars are converted, the mash has about 5% alcohol and is ready for distilling.
Usually copper pot stills (alambiques) are used for distillation, but there are also clay pots (ollas) or pots made from different plants (reed, agaves, bamboo, wood etc). All of these forms don´t allow for continuous distillation, which means that each portion has to be distilled completely before opening the still to refill it. The most popular still is the alembik from copper with a container for the mash (olla, cucúrbita or retorta), a seperable helmet (cabezote, montera or capitel) on top of that which leads the vapours into a tube (turbante or pasa-vapores), ending in the worm condenser (serpentín or culebra). There are no bubble trays, spirit safes, meters or any other devices applied.
Mezcal Minero is produced in stills from earthenware pots. The container for the mash is an amphora-shaped clay pot, which is fixed into a mud brick oven, heated from below with firewood. A clay pot with openings at both ends (montera), is placed on top of that to receive the vapours. The condenser, a copper pan (cazo), is placed on the upper opening and contains cold water. On its curved bottom the condensed liquid gathers and drips into a wooden spoon (paleta) fixed underneath and then is led by a hollow reed to the outside of the still. The spirits produced this way have a very individual character and an extraordinary grade of purity. Therefore Minreo is considered to be one of the best Mezcales available. The challenge in producing it is in the handling of this unusual still and its delicate clay pots.
Usually Mezcal is distilled twice, in the region of Oaxaca along with the solids from the fermentation. In other regions, however, distillers prefer to use only the liquid parts, as Tequila-producers do.
1. Distillation: The still is filled with the liquid parts of the mash and –in Oaxaca- with the solids to equal parts. During the heating process a liquid containing around 20% to 30% of alcohol is obtained (ordinario, común oder shishe), similar to running a wash still in Whisky production.
2. Distillation: The second run (rectificación) produces heads (puntas or cabezas), heart (cuerpo, corazón) and tails (cola). The heart is now also called Mezcal and has a graduation between 45% and 55% of alcohol. It is consumed at the strength it comes out of the still, without being diluted with water.
The spirit is controlled during its distillation by dropping a small amount of liquid from a height of 50cm into a bowl, mostly a gourd (jícara). It produces small bubbles (perlas, perlado), which give the master distiller information about the specific properties of the spirit, mostly its alcoholic graduation. The bubbles should form a closed ring along the side of the gourd (cordón de perlas or "string of pearls" ) and last as long as possible. The distillate is also rubbed by the distiller into the palms of his hands in order to monitor the smell and feeling of evaporation. A traditional palenque has no meters or other devices to control the product. Quality depends on the experience of the master distiller. Chemical examination is undertaken in certified laboratories since the introduction of the standard, controlled by COMERCAM. During each step of the process samples are taken and tested.