Do you remember the steps of the tequila production from the certification course?
That was the traditional production process.

The modern production method refers to a new automated process where the production is designed to remove all of the manual labor intensive elements except for the harvest, which is still done by the jimadores.

As the demand for tequila was getting higher, the biggest producers started to invest in technologies that would allow them to make the production more efficient, cost-effective. While this idea goes against the ideology of the denomination that the land, the water and the special local artisanal processes together should make tequila unique, yet the industry found this evolution to be necessary for tequila to become a truly international, global drink.

So while the traditional way works with batches and is very labour intensive the modern way is all about automation and continuous processes.

The agave farming and the harvest as mentioned earlier is the same.

Cultivating agave is considered to be a risky investment (and it requires a high level of micro- management), so big producers buy most of their agaves from small farmers.

The individual farmers don’t have the capital to invest in technology for more efficient farming, so cultivating and harvesting agaves remain an old-school process.

On the other hand, once the agave arrives into the plant and is loaded onto a conveyor belt, the rest of the process is mostly automated.

The conveyor belt passes through a few shredders to shred the agaves into tiny pieces.

Then they enter a chamber called the diffusor or diffuser in English. The diffuser uses hot currents to wash the sugar s(or more like the inulin, fructans, starch) from the plant and separate them from the fibres.

After this, the liquid passes through to be hydrolysed or with other word cooked in autoclaves. This is the exact opposite way of the traditional method, where the agave is cooked first then shredded and milled for extraction.

The process is a lot more efficient ​achieving over 95% efficiency when extracting the sugars of the agave.
However it does not allow many small refinements traditional producers can apply and the efficiency has its cost for having ​too many molecules in the fresh distillate that are not necessarily appealing​. These need to be removed through extensive filtration (including triple distillation and high proof/abv column distillation) which in turn can make the tequila lighter and less unique.

Pot Still vs Column Still

Distillation in a pot still is the old-school batch distillation - it is a lot more manual process, where during the distillation certain parts of the distillates are collected or discarded.

As the temperature rises in the still, at a certain temperature point, the more volatile components start to rise from the bottom of the still and are captured at the top of the still as they condense. What they capture and what they discard is broken down into three parts​: head, heart and tail.

Most producers discard the distillate obtained in the first few minutes (called: ​the head) as it can have aromatic components that they don’t want in their tequila.

This first discarded part is called the “head” or “cabeza” of the spirit. ​The “heart” or “corazón” contains the most precious components and it is collected separately to be used in the final product.

Once the flow from the still reaches a certain alcohol content, they switch from collecting the heart to collecting the tail​. Leaving too much of the tail may make the tequila taste of citric fruits or olives. While single distillation in theory is allowed by the regulations, no producers seem to apply it and instead they double distill. There are a few triple distilled tequilas - distilling it for a third time however may remove some precious aromas from the tequila.

Pot stills come in two materials copper and stainless steel. Tequilas made by copper stills are usually regarded as superior (not to mention the material is approx. 10 times more expensive), however stainless steel made tequilas can be just as good. There are so many other things that impact the quality of a tequila, even the shape of the still!

The best way to describe the ​column still ​is like a series of pot stills on top of each other forming a vertical tube.

Unlike in the case of a pot still, where distillation is achieved by one batch at a time, a continuous still in theory can operate 24 hours a day without any disruptions. There are multiple plates inside the tube, and basically the distillation happens in between the plates.

The mosto muerto which is basically agave beer is released from the top of the still while the bottom of the still is heated and they release steam into the system.

As the warm steam from below interacts with the mosto, there is an exchange of heat and molecules. Heavier, less volatile elements with higher boiling points get pushed to the lower plates and the more volatile elements with lower boiling points(like the ethanol) will rise to the higher plates. The higher the plate is located from the bottom of the still, the higher is the level of its alcohol(ethanol) content. Then at the top of the still, the purified alcohol is collected.

Column stills are regarded as inferior to pot still.

Most producers using column stills are volume oriented large producers, however as always there are some rare exceptions to this rule too.
La Tequileña (producer of Don Fulano) has column stills (as seen on the pictures), however they use it at a low alcohol strength leaving lots of aromatic components in the spirit. And even they blend their column still tequila with copper pot still batches and the majority of the blend is from the pot stills. Another example is Armagnac, the spirit where column stills are utilized for smaller batches and low still strength to achieve high aromatic quality.