Mezcal guides

How is Mezcal made?

This handy little guide will walk you through the production process of mezcal. Mezcaleros, mezcal makers, use the techniques outlined below to craft this incredible and delicious Mexican spirit.

Traditionally, mezcal is handcrafted by small-scale producers. Just one village could contain dozens of fábricas or palenques, local distilleries where mezcaleros use methods passed down from generation to generation.

In every stage of the mezcal-making process, there’s a different way of doing things. In 2016, three grades of mezcal were defined: Mezcal, Artesanal and Ancestral depending on the techniques used, all of which are explained in our Different Types of Mezcal guide.

No two mezcals are made exactly alike, but they all begin with the same thing: agave. So let’s start there.

Jump to section

Author:

Reading time: 5 minutes

Step 1: Harvesting the Agave

Mezcal is made from the agave plant, a succulent native primarily to the arid and semiarid regions of the Americas. It has recognisable large rosettes of thick, fleshy, cactus-style leaves that can vary in size, shape, and colour depending on the species.

There are about 200 species of agave, with a wide range of uses. The fibrous leaves are used in making traditional Mexican handicrafts, such as ropes and mats, while you may have tasted agave nectar before. It’s in most supermarkets these days.

Agave is also known as maguey in Mexico. Maguey may be cultivated, semi-wild, or wild from over 30 agave species, varieties, and subvarieties. Each has its own growth cycle, taking 5 to 30 years to mature (depending on the species and growing conditions) and they vary in size but can grow up to 2.5 metres (8 feet) tall. When agaves mature, they produce a tall flower stalk, often several metres high, which blooms with numerous flowers. After flowering, the agave typically dies, leaving behind seeds, offsets (also known as pups), or both.

The agave espadín (which brilliantly means smallsword and has the less exciting scientific name of A. angustifolia Haw) is the most common maguey due its ease of cultivation and approachable, versatile flavour profile. It is nearly always farmed as opposed to growing wild. Truly wild magueyes are rapidly disappearing in Oaxaca (pronounced 'wo-ha-ka'), the state with the highest percentage of mezcal production, but across the other mezcal-producing states there are semi-wild and wild species of agave that are cultivated. Semi-wild maguey is planted (from seed or hijuelo) and left to fend for itself until it is harvested years later. Just as the gods of mezcal intended.

Harvesting mature agave is a labour-intensive and skilled job for the farmer or jimador. It entails cutting the leaves and roots away with a curved tool that has a heavy semi-rounded blade on a long rod called a coa. They do this to expose the heart of the agave, called the piña. Because it looks like a pineapple. A big pineapple. They can weigh up to 100kg (220lb) but usually come in at 30kg, still quite hefty. This makes them difficult to harvest and transport.

So why bother? Well, the piña is full of sugar that can be fermented. As you can imagine, a massive ball of sugar is quite appetising to a lot of creatures, so that’s why the plant has spikes and stores its sugar in an indigestible way. On that note, did you know that 80% of agave pollination is due to the humble bat?

To get those sugars, you need to cook the agave. That’s step two.

Jimadors harvest agave. Image credit: Mezcal Amores.

Step 2: Cooking

The piñas are then roasted to convert the complex carbohydrates into fermentable sugars. This is traditionally done in a conical earthen pit dug into the ground. The pit is lined with stones, either piled on red-hot embers or heated in a fire. Fireproof Lava bricks preheated by burning wood are used too. The piñas are placed on top of the stones and then covered with layers of wet maguey fibres (bagazo) and/or leaves, sometimes banana leaves, straw mats, or tarps are used too. This piña pie is then buried under a layers of stone, earth, and/or clay and left to slowly roast for several days. Just like mama used to make. This stage can impart a distinctive smoky flavour you probably have tasted in a mezcal before.

While not common, cooking with gas or using autoclaves and steam ovens does occur. But it’s only permitted in the production of what is sometimes known as industrial mezcal but legally is just classified as mezcal (as opposed to ancestral or artesenal). This is because they’re more efficient, but they don't impart the same flavours as the slow roast and they’re not traditional. Like cauliflower at Christmas.

Agave piñas being cooked. Image credit: Corte Vetusto Mezcal.

Step 3: Crushing

Once the cooked maguey has been removed from the oven, cooled, and sorted, the roasted piña is then ready to be crushed/pressed/milled in order to separate the wet pulp from the fibre and to release agave juice (aguamiel) and sugars ready for fermentation.

There are various methods for doing this. Tiny, local distilleries will load the brown piña into a trough or hollowed tree trunk and then pound it with wooden mallets. But the most traditional way is to use a stone wheel called a tahona pulled around a circular stone pit by a horse or small tractor. Some modern producers use mechanical crushers or a roller mill. For ancestral mezcal, anything mechanical is forbidden.

Agave piñas crushed by a tahona. Image credit: Corte Vetusto Mezcal.

Step 4: Fermentation

Fermentation, more than any other step in mezcal production, is really where the magic happens. Traditionally mezcal is made in the wild, with natural yeasts and fermentation vessels with little of the conformity or homogenisation from region to region.

After the crushing, our juice and fibres from the crushed piña need to be transferred to vats to ferment. The average size is about 1,000 to 2,000 litres, but for smaller or more traditional operations, the vats can be as small as 300 to 500 litres, while in more industrialised settings, fermentation vats can be much larger, potentially holding up to 10,000 litres or more. Larger vats let you produce more in one batch, smaller vats offer more control and variability, so the choice of vat size will influence the character of the mezcal.

Traditionally these are wooden – oak, cypress, pine – favoured due to the availability of these wood types (always handy) and due to their insulating properties and lower thermal conductivity, helping maintain a consistent fermentation temperature. These are called tinas.

Lots of other materials are used, however, like stone or concrete. Ceramic, while not the simplest to maintain due to its fragility and not ideal due to the small volumes it produces, is popular and traditional, offering temperature stability and a microbe-rich environment. We also see examples of ancestral fermentation pits in Nayarit and Chihuahua made from bovine hide, a very traditional method that produces all kinds of flavours, but is not exactly efficient.

Stainless steel isn’t traditional and doesn’t offer much in flavour development, but large producers like its capacity, predictability, and ease of maintenance. The same can be said of plastic vats, often subsidised by the government, which are an affordable, easy option (save for the risk of chemical leaching if not managed correctly), but given this is a spirit all about utilising a rich microbial environment these vessels are not widely used or respected.

Mezcal primarily undergoes wet fermentation, which means that water and crushed agave fibres are combined in vats where natural yeasts and bacteria are allowed to do their thing. In Tequila production, the fibres are filtered out, this is given as a reason why mezcal is regarded as a more authentic and complex product.

It’s vital to have access to clean, fresh water sources, whether that’s from fresh river water or private wells feeding directly to the palenque. Each is unique, boasting individual mineral contents that contribute flavour and mouthfeel to the final product and bolster the notion that mezcal can reflect the place it is made in and reflect a certain provenance.

Dry fermentation is also employed. This means that after the agave is roasted, it’s exposed to the open air at the palenque to absorb the diverse local microorganisms. A thin layer of mould may appear, or there may be no visible change, but biological activity is occurring, like the way mould develops in cheesemaking, decomposing the plant material and developing flavours.

There’s so much variation in mezcal fermentation that means there is no singular process to ferment. In places like San Luis Potosi and Durango it's commonplace to use the agave juice obtained in the crushing stage for fermentation, while large-scale mezcal producers will often strain out agave fibres to increase their yield.

Whatever method you choose, yeast is the key. Nature’s magic dust, eating sugar and pooping out alcohol (science, baby) is harnessed from the environment, from airborne yeasts microbes endemic to the palenque, those found in the fermentation vessels (assuming you’re not using plastic or stainless steel) to the yeasts from the skins of the maguey. All these diverse strains produce acids and enzymes that release terpenes in the agave and generate the flavours and aromas we’ll taste and enjoy in the eventual spirit. For mezcal, you NEVER add additional yeast, accelerants, or chemicals.

As yeast breaks down sugars in the mash, it generates heat and carbon dioxide over a span ranging from a single day to multiple days. During this phase, the mezcalero diligently oversees the fermentation, using a tree branch to measure the temperature inside the vat through an opening filled with dense agave fibre. This approach helps determine the heat levels at the vat's bottom as the branch warms to the mixture's temperature. Additionally, the mezcalero monitors the evolving fragrances, from the initial sweet aroma of roasted agave to the more intense smells of fermentation and alcohol.

During fermentation, a crust forms on the surface, which must be regularly disturbed to prevent any acidic buildup, potentially compromising the mezcal's quality. Some distillers choose to retain the crust for a sharper taste, while others break it up to ensure a smoother mezcal by improving yeast's oxygen access. The vat is not fully filled to leave room for the expansion from the produced carbon dioxide.

A traditional mezcalero engages all senses—watching, listening, smelling, touching, and tasting—to evaluate the fermenting mash as the sugar decreases and the alcohol content increases. They rely heavily on tasting and smelling to track the fermentation's progress, often using a hollow reed to draw samples from the vat. When the sweetness disappears and the liquid tastes sour and slightly alcoholic, it signifies the completion of fermentation.

The resulting liquid, known as mosto, typically has an alcohol content between 4-9% ABV and bears similarity to pulque, a traditional Mexican beverage.

There is no fixed or even really typical length of fermentation as it is dependent on many factors: the sugar content of the pina, how warm the weather is, the altitude, of the palenque, proximity to livestock, how frequently the palenque is fermenting… all of these individual elements have a part to play, meaning fermentation can last several days during the summer to a week or so in the winter.

Fermentation is arguably the most important stage of mezcal production. Image credit: iStock.

Step 5: Distillation

Once you are the mezcalero with the mosto, then you purify the liquid and increase its alcohol content with a handy bit of science called distillation, which creates a lovely clear liquid that will become the mezcal itself. Mezcal is typically double-distilled, but it can be triple-distilled or distilled just once. There’s no legal restriction here, but for the purposes of this educational guide, we’ll run through the common double distillation process.

During the first distillation the most volatile compounds, such as methanol, run off the still first and these are known as the heads, or the puntas. Some, or all of these are redistilled in the second distillation, as is the tails or colas, which run off the still last after the distiller has made their cut to attain the heart, or el corazón, the desirable spirit. The first distillation produces a weak alcohol around 20% ABV called ordinario, común, or shishe, depending on the region.

The ordinario is then redistilled (how much of the heads or tails are distilled with it is down to each individual mezcalero’s preference). The same process follows during the second distillation: the puntas run off the still first again, followed by the el corazón which are collected to become the mezcal that is either aged or bottled, then finally the colas. The skill of the mezcalero is firmly rooted in their ability to make the cuts that separate heads, hearts, and tails.

The mosto is distilled in pot stills. Mezcal cannot be distilled in column stills, although a form of still is used (primarily in the state of Miahuatlán) that is a type of copper alembic still with a refrescadera - a mini-column. Most commonly used is a more classic style of copper alembic still, but you do also see the old school “Filipino” clay pot stills, with their distinctive bamboo-like tubing. These were the original stills used to create mezcal.

Mezcal can be distilled in a number of still types. Image credit: Corte Vetusto Mezcal.

Step 6: Ageing (optional)

Many mezcals are bottled immediately after distillation as joven (young or unaged). However, some are aged in wooden barrels to develop additional flavours. The categories of aged mezcal include reposado (rested) for 2 to 12 months, añejo (aged) for over 12 months, and sometimes extra añejo for more than three years.

Step 7: Bottling and drinking it!

Finally, the mezcal is bottled. On a very small scale, this is done by hand, on an industrial scale a bottling line will be used.

The mezcal is now ready to be consumed. Huzzah!

Each step in the production of mezcal, from the selection of the agave plants to the distillation, influences the flavour profile of the final product, making each mezcal unique. The methods and the variety of agave species used contribute to the wide range of flavours and aromas found in mezcal, from sweet and fruity to smoky and earthy.