The Different Methods Of Cooking Agave
by Greg Rutkowski
Ever wondered how many different processes are used to cook agave? From traditional techniques to modern technology, let's go on a brief ride through the agave cooking process to make your favorite agave spirits like tequila, mezcal and raicilla.
According to the book Mezcal: Un Espirituoso Artesanal De Clase Mundial by Domingo Garcia (Spanish), cooking the agave is the second most important process that impacts the flavors and aromas of any given mezcal.
Here is a list of all of the cooking techniques from the most traditional to the most modern.
The Earthen Pit
In Mexico it can also be called barbacoa or horno de piedra, which roughly translates to “rock oven.”
This style of oven dates back to the prehispanic era (9,000 years ago). Only, back then it was used by natives to cook agaves to be eaten, not distilled into alcoholic beverages.
In essence, the earthen pit is a large hole in the ground that can be as deep as ten feet. The hole is sometimes lined with volcanic rocks, river rocks, bricks or even concrete. Other times its lining is simply the earth itself.
With this method, you have little to no control over cooking temperatures. However, these natural inconsistencies are often sought after because they enhance the flavor profile and add more complexity to the agave distillate.
To start the oven, a fire is built at the bottom of the pit. Most mezcaleros are particular about the firewood that they use. Oak is the most famous type of wood used all around Mexico wherever agave distillates are traditionally made.
Only the mezcaleros can decide when the temperature is right, opting to use their senses and instincts instead of a temperature gauge. After the fire is at the correct temperature, rocks are then placed on top of the hot embers.
Once the rocks are properly heated, a layer of wet bagazo or used agave fibers are placed on top of the rocks to prevent the agaves from being scorched.
Now it is time to stack the agave piñas around the oven.
Stacking the hearts of the agave is a very strategic process. Here the mezcalero puts the largest agaves nearest the center and the smallest agaves on the outside. Typically the core of the agave will be pointing toward the inside the oven for better cooking.
Many mezcaleros will cook different types of agave at the same time. Alvin Starkman said in his book Mezcal In The Global Spirits Market: Unrivaled Complexity, Innumerable Nuances that when different agaves are cooked together like this, it impacts the flavor. This sounds obvious, but when you buy a bottle of tobala mezcal, you will never see any indication on the bottle that the tobala used to make the mezcal may have been cooked in an oven alongside espadin, tepeztate or madrecuishe. And only a true mezcal connoisseur will be able to pick up on these subtle nuances in the flavor.
After loading four to ten tons of agave into the pit, it is time to seal the agaves in.
In order to seal the agaves, mezcaleros use a combination of dirt, plastic sheeting, wood, tarps, palm leaves, stones and other materials to keep the steam from escaping. The main goal is to seal the oven as best as possible.
Once the pit is fully sealed, traditional mezcaleros will adorn the oven with a cross and say a blessing.
When this process is complete, it is also common for the workers to share a celebratory drink of mezcal themselves.
The agaves will cook for three to five days, and then have a cooling period of 24 to 48 hours.
After this, the agaves will be ready for the milling process.
Oftentimes, the horno needs to be repaired. Because of the high heat, the rocks will fracture and need to be replaced. These types of repairs usually happen during the off season when distillation is not taking place.
The Adobe Oven
The adobe oven is also a prehispanic invention that is still used today to cook agaves. Interestingly enough, this type of horno is unique to the state of Jalisco and is used to make raicilla de la sierra, meaning “of the mountain.”
It is one of the lesser known cooking styles and it seldom contributes smoky notes to the flavor profile despite using firewood as its heat source. This is because the fire is only used to bring the oven to its desired temperature, not to actually bake the agave. It is only after the flame is put out, the wood is removed and the ashes are swept away that the agave is placed inside the oven.
Because its round shape evens out heat distribution and uses less firewood, the adobe oven is generally considered more efficient than the earthen pit.
Today you typically see this horno built with brick for structural support and lined with clay on the inside and outside. It is truly fascinating to behold on account of its unique shape and difficult construction.
One downside of this style of oven is that the capacity is usually only limited to two to four tons of agave making the batches a lot smaller. And not unlike the earthen pit, it often requires frequent repair. Lastly, it is labor-intensive, and one has to feel bad for the workers who must crawl inside after the baking has been completed, as the oven is still piping hot and full of smoke.
If you ever travel to the Puerto Vallarta area, this is a spectacle worth going out to the mountains to see for yourself.
Oftentimes the adobe oven gets classified in the same category as mamposteria, but I think it's important to distinguish them because the heat source is quite different.
The word mamposteria literally translates to “masonry” in Spanish, a fitting name considering they’re often made of bricks, cinder blocks, concrete and clay, among other things that can be mixed with water and sand. A heat source like steam or LP gas is installed with tubing and mechanisms to generate heat.
The purpose of the mamposteria horno is to have more control over the cooking process and to eliminate the use of firewood. Although, technically, this type of horno could accept firewood as well.
You will see the mamposteria horno most often used in tequila. Amongst tequila aficionados, this is considered the true traditional cooking process; however, as shown above, there are technically more traditional processes than this.
According to the book El Arte De Conocer, Saborear y Admirar Tequila by Juan Bernardo Torres Mora (Spanish), it was around the 1870’s when the tequila industry adopted steam. This was during Porfirio Diaz’s industrialization of Mexico when businesses were incentivized to streamline manufacturing processes.
Today, there are some other known agave spirits distillers around Mexico that also use this process if the firewood supply becomes an issue or if the distiller is trying to nail down a certain flavor profile.
This is a far more expensive option in terms of upfront costs than the previous options and is typically reserved for bigger agave spirits manufacturers or as a communal horno shared amongst a group of mezcaleros.
Sometimes the walls need to be up to one meter thick to help insulate the agave and prevent any heat from escaping. Even so, you will often see the heat escaping from the door anyway, as it is difficult to completely seal.
Cooking time usually takes between 48 and 72 hours with a 24 hour resting period before milling.
On a final note, one advantage of the mamposteria horno is its ability to collect agua miel or agave syrup. The collected agave syrup can later be added to the fermentation process or sold as a natural sweetener.
The autoclave is considered the point at which a lot of people draw the line between artisanal and mass-produced agave spirits. It is commonly found in tequila production, but it is also used to produce industrial mezcal.
The autoclave is a large cylindrical chamber that resembles a nuclear warhead, but it’s essentially a giant pressure cooker.. A combination of water and heat is used to create pressure within the chamber. The heat from the steam cooks the agaves at a stable temperature for a set amount of time. An autoclave can completely cook a large amount of agave in as little as 8 hours. .
The autoclave is also used for many other purposes such as sterilization, vulcanization, air removal, hydrothermal synthesis and industrial cooking. It is the preferred method of many large agave spirits producers because it’s highly efficient and you have a great deal of control over many variables in the process.
Efficiency is gained because you do not lose as much agua miel (agave honey), cooking time is reduced, and it’s far less labor-intensive than previous methods.
Still, it’s not as simple as pressing a button and walking away. Everything from the arrangement of the agave to the intensity and duration of the heat needs to be carefully considered to ensure the highest quality product. It may seem one-dimensional, but there is even an art to cooking with an autoclave.
Of course, many would argue that this is a less authentic method of cooking agave, and although the autoclave doesn’t necessarily compromise the quality of the finished product, much of the complexity of the flavor is lost due to the sterility of the process.
Just imagine all of the natural flavors with which the agave is imbued when cooked in an earthen pit with soil, rock, wood and fire versus when cooked in what is essentially a vacuum.
And yet, there are some who might actually prefer the cleaner, more neutral mezcal flavor that results with the autoclave method. Bearing all of this in mind, I’d argue that even the artisanal-leaning mezcalero should not discount this method entirely.
When you visit the bigger distilleries in Tequila, Jalisco you may notice a long boxy looking industrial machine with lots of tubes. This multimillion dollar machine is called a “diffuser” and it defines what mass production tequila is.
The diffuser method is the most efficient method of cooking agaves because it achieves a nearly 100% extraction yield. Using chemicals such as sulfuric acid and ammonium sulfate, a diffuser can cook agave in as little as four to eight hours. The fermentation process is also jump-started using this method.
How Does a Diffuser Work?
In an article posted by Casa Sauza,
“The diffuser working process is based on the systematic wash of agave bagasse which swims against the current through the water. In the practice, this is achieved by forming a "bagasse bed", which is previously torn apart into small pieces on a transporting chain.
Some water is added in the opposite side of the transporting chain, and its filtered through the agave bagasse bed and the small holes of the chain.
Water dissolves the contained sugar in the agave bagasse, extracting a juice that has plenty of this sugar, after this, it is recollected in a special tub. The juice moves pumping along the diffuser to the next stage and the process is repeated till the juice reaches the maximum concentration level at the final point of the diffuser.”
This method is the most criticized method of cooking agaves, as it is unnatural and inauthentic because it uses chemicals and it is industrial. However due to the need to become more efficient, many larger producers have opted to implement the diffuser in their process.
This method is by far the most expensive as it requires a lot of machinery and consumables to run.
The Problem with Diffusers
Although fast and efficient, diffusers are the bane of both the tequila and the mezcal industries. In this method, monumental amounts of agaves are rapidly processed before they fully mature, creating agave shortages and leaving smaller artisanal mezcaleros to pay the price. Because the agaves are so raw, they often have to be soaked in acid in order to soften them before they’re shredded into raw fiber. This is already sounding tasty, isn’t it?
The agave is not actually cooked; instead, the starches are boiled out of the shredded agave and treated with enzymes to convert them into sugars. The numerous chemicals and excessive distillation render the agaves stripped of all their natural flavors except for a cheap vodka-like “medicinal” taste. This taste is then masked by introducing even more chemicals and adding flavor on the back end much in the same way it's added to processed foods. Anyone who has developed the least sophisticated palate for mezcal will be able to taste the poor quality immediately.
Perhaps more offensive than the adulterated process and the artificial taste is the fact that these mass-producing distillers will then pass their brands off as “100% agave.” While this isn’t exactly a lie, it’s a far cry from the truth to the misinformed public and it’s an insult to the hard-working mezcaleros who are actually creating an authentic product. I advise everyone I meet to do their research on Tequila Match Maker before investing in these brands who have utterly abandoned both ethics and quality for greed. The taste alone should be enough warning.
Other Resources About Diffusers
AGAVE PINA COOKING METHODS (TEQUILA) ..... INCLUDING DIFFUSER - Long Island Lou
There May Be Too Much Agave in Your Tequila or Mezcal - Mucho Agave
Greg Rutkowski, President of Mezcal For Life
Greg is a certified Agave Spirits Advisor and Mezcal Sommelier through the Agave Spirits Institute. He contributes to a number of agave spirits projects inside Mexico including Raicilla tours and also his agave spirits distillery in Puerto Vallarta, Jalisco.