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Updated May, 2011

How Tequila is Aged & Bottled

Part 1: Aging


Miguel Cideno Cruz, plant manager of Tequila Herradura, was quoted as saying, "When we have the white tequila, straight from the still, we say it is like having a beautiful woman. Then you can dress it how you want it, you can use French white oak barrels instead of American oak, put it in sherry barrels . . . You try to be consistent but there are no two equal tequilas. So we are dealing with something alive."


CRT barrel seal

Small barrels at TapatioOf the five types of tequila, blanco (also called plata, white or silver) and joven (a mixto) are not aged. Blanco tequilas may be stored in sealed, stainless steel tanks, but this does not age the tequila.


Reposado, aņejo and extra aņejo are all aged in wooden (oak) barrels or tubs. The wood imparts a smoothness to the tequila, as well as infusing the tequila with the wood oils. These react with the tequila to create new flavours and tastes beyond the original agave; often a complex mix results.


All aged or stored tequila must be kept in containers sealed by the CRT (see seal, above). Most companies purchase used barrels from international distilleries; a few purchase new barrels, but they are not often seen. The most common barrels in use are previously-used American whisky barrels (Jack Daniels is the most commonly seen). However, there are also Canadian and French barrels to be seen in use.


Francisco Hajnal, Cuervo's maestro de tequila - a sommelier for tequila said that tequilas aged in American oak were sweeter than those aged in French oak. He said Cuervo also used barrels from Jerez, Spain (Jerez is the home of sherry).


Barrels last 25-30 years, but each has only a five-year lifespan for any batch of tequila, after which all of the tannins are fully immersed into the tequila. After each use, the amount of wood absorbed by the tequila gets less and less, so the tequila must spend longer time in them to be affected by the wood. Barrels are used at most five times before being discarded, or used for parts to repair other barrels.


New barrels at Agave TequilenaAll aņejos are aged in small barrels no larger than 600 litres (most are around 180-200 litres). Most producers buy used barrels for this purpose because new barrels will express considerably more wood into the product and could change the flavour much more. New barrels are also considerably more expensive than used barrels ($300-$400 each). The most popular barrels for aging are American oak, such as Jack Daniels' whiskey barrels, although both French and Canadian barrels are also used. La Alteņa uses bourbon barrels.


Barrels and reposado aging tankAt some distillers, new barrels are used for reposados which sit in the wood for a short while before being transferred to older barrels. All reposados can be aged from two to nine months.


Then the barrels are used for aņejos, which sit for between one and three years (aņejo) or more than three years (extra aņejo, a new category introduced in 2006). This rotation lets the wood mature the reposados, so not as much wood will infuse into the Pink reposado from Asombrosolonger-resting aņejos. Almost all reposados and aņejos are blended with other barrels of the same age.


Asombroso introduced a new twist by aging their reposado tequila in red wine (Bordeaux) barrels. This infuses a noticeable pink tinge to the tequila, and makes the reposado a little sweeter than that aged in whisky barrels. This shows the effect the previous use of the barrels can have on the final product. Asombroso has two different pink reposados: one aged three months, the other 11 months.


Clase Azul has a new, limited production, Ultra tequila which they notes has been, "Aged patiently for a minimum of three years in hand-selected, ultra-fine sherry oak barrels."

Wood also darkens the tequila, so newer barrels can rapidly make an aņejo very dark and add considerable wood to the tequila. This can be mitigated by using older barrels not as likely to infuse the tequila as much. Note too that changing barrels (replacing old ones with new) can also darken a tequila and change its flavour until the barrels are 'broken in.' The colour of a tequila does not necessarily reflect either age or quality.

Barrel seal at El Tapatio's bodega, ArandasReposados may also be aged in large wooden vats of 20,000 litres or more. The amount of wood contact per surface area is much less in a vat than in a small barrel, so reposados from these vats tend to be lighter, with much less wood effect.


A good bodega (barrel storage) is cool and dark. Barrels are affected by humidity and heat. If it's too hot, or too dry, the wood dries out and more alcohol is lost. That's one reason most distillers keep their tequila at 110 proof (55% alcohol), so it has some extra to lose. An uncommon but highly effective method of keeping the wood from shrinking is to use a mister system in the bodega. An underground or basement storage area is best, but where not possible, a closed, temperature- and humidity-controlled storage room is also good.


El Tapatio does not distill to a higher level, then add water to lower the alcohol as do all other distillers. Instead, they stop distillation when the alcohol is at 80 proof. Since barrels lose alcohol during aging, however, El Tapatio distills some tequila to 100 proof twice a year, to add to the barrels to restore the weaker tequilas to their original proof.


Loss in the barrel during aging can be high, depending on storage conditions. The average is 5%-10% per year. El Tapatio, in the highlands, which has its bodega underground, has an evaporation rate of only 2-3% a year, sometimes less, compared to 8-10% above ground.


The final product is usually blended with other barrels of a similar age to create a consistency of taste and aroma.


In an interview on, Robert Denton, former distributor of Chinaco and El Tesoro de Don Felipe tequilas, said "Aging tequila is a masterful skill, one that’s more art than science. It requires many years and an exceptionally keen palate to do it really well.  Our tequilas are aged in 180-liter oak bourbon barrels. The smaller barrels allow for greater quality control and impart more wood character to the tequila."


BodegaRepresentatives of the Tequila Regulatory Council oversee the production to ensure the distillers meet the standards and quality controls in place under Mexican legislation. The resulting mix is then bottled or (if a mixto) tanked for bulk shipments. A few 'single barrel' tequilas are available in the premium market.


All 100% agave tequilas must be bottled in Mexico and marked "Hecho en Mexico" - made in Mexico. Only mixto tequila is allowed to be sold in bulk and bottled outside the country.

"Distilled from melancholy and from lucidity; from an intense love for good; from a need to bite into the earth and hear the poetry of the people's song."
Author unknown, quoted in the Guia de Tequila, published by Artes de Mexico,1998.


How long can you age tequila in barrels? Conventional wisdom a few years back put a limit of 4-5 years (El Tesoro Paradiso is a five-year-old tequila). After that, it was said the tequila would lose too much alcohol, or become too woody. However, over the past decade producers have been pushing that envelope, and pressuring the CRT is allow a new category for older aņejos. The extra-aņejo category was approved in 2006. In 2007, some of these extra-aged tequilas started showing up on the market at five-six years old. In 2007, the author visited some companies which had tequila in barrels in storage already seven and eight years old. There are rumours that ten-year-old tequilas will even be on the shelf in late 2007.


While mixtos are generally not aged, but rather get their colour from caramel or other additives, there are several brands that are actually aged in wood and will be noted as reposado or aņejo. This became more common during the agave shortage when several producers replaced aged 100% agave tequilas with aged mixtos. While today many of those brands have reverted back to 100% agave, not all are. The label must say 100% agave to be pure. 


Samll barrel for home agingIt is possible to age your own tequila (usually blanco). Many companies make small oak barrels for that purpose. However, since these are new wood, and there is a high surface-to-wood contact ratio, they can infuse the tequila very quickly. Some experimentation and monitoring of the process is required to get what you want from this method.


The type of barrel used in aging reposado or aņejo varieties also makes a difference to the flavour and colour. Some distillers use French oak, others white (American) oak. Many buy barrels already used to age Scotch or Bourbon. Redwood is also used. The length of aging in the barrel also affects the tequila - many distillers only age their tequila in barrels for the required do days (reposado) or one year (aņejo) and may rack it into stainless steel tanks after that to prevent further impression from the wood. Some aficionados feel too much wood can overpower the delicate agave flavour.


A few enterprising producers have put together aņejo blends. Tequila Lapis, for example, blends tequilas that are 2.5 to 4 years old. Tres-Quatro-Cinco is a blend of three-, four- and five-year-old tequilas. The new extra-aņejo tequilas will likely see other interesting blends of much older tequilas. In 2008, I sampled a 13-year-old tequila from Asombroso, and while interesting, found it a bit too woody for my palate.


As the tequilas age, the wood of the barrels will shrink and expand according to the current climate and humidity. This allows air and moisture to mingle with the tequila, creating a product that will be unique to its own microclimate. Single malt scotch makers have found that the proximity to the ocean creates different products because the salt-laden air affects the aging scotches. As far as this author knows, no tequila manufacturer has yet experimented with aging tequilas in a bodega close to the Pacific to see how it would affect the resulting tequila.


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Part 2: Bottling and labelling

Tapping in corks at El AgaveBottling is done using automated filling machines, and may also include a production line for washing bottles (automated), placing a stopper or cork (sometimes done manually), applying labels, and checking for clarity and quality control. In some cases, labels are even hand-painted.


Bottling line at El AgaveBefore bottling, the distilled tequila is filtered through cellulose filters or activated charcoal to remove any solids.


The tequila is usually blended, and the blender has the important role of maintaining consistency with previous batches, using his senses to  help blend just the right amounts from each barrel or tank to produce the product.


Bottle filling machine at PartidaBulk (mixto) tequila is placed in large (25,000 litre) tanker trucks and driven across the border to be bottled in the USA.


Checking bottles at El AgaveBottles are washed (sometimes in tequila!) and drained, then filled with the tequila. Most bottling machines at smaller producers are equally small, taking four-eight bottles at a time, but the larger producers have a much more efficient bottling line. Filling may sometimes require a worker to top up or siphon off tequila as necessary.


Applying labels and sealing bottles at Agave TequilanaSome companies still fill every bottle by hand, rather than by machine. While this may see very labour intensive, remember that labour is generally less expensive in Mexico than high-tech equipment. Plus many of those companies believe that hand-filling is part of the hand-crafted production process.


Topping up bottles at Agave TequilanaWhile the cork is still the traditional stopper, several companies have gone to a plastic pour spout to prevent the bottles from being refilled at stores, bars or restaurants. There are also screw-tops and plastic 'corks'.


Once filled and the stopper is in place, bottles will be inspected for any flaws, or for any impurities in the tequila.


Label painter at Don Valente'sCorks may be pounded in by a person with a small mallet, or by an automated corking machine, or a combination. Labels and cork seals can be hand-applied or machine-applied. In Don Valente, the labels were even hand-painted.


Some premium bottles are also hand-painted. Casa Noble's black-and-gold aņejo bottle, for example was hand-painted with real gold paint, making it a collectors' item today. Some producers have the artist sign the bottle.


Los Azuelos bottleOther collectibles may be in the glassware: Porfidio created a splash with its cactus-bottle which set a trend for producers to followed with similar artisan bottles, including companies like Pura Sangra and Voodoo Tiki. Miniature tequila bottles are another collectible item, as are any company-labelled or monogrammed items like caballitos, coasters, T-shirts, etc.


At El Tapatio, even their labels are put on by hand, with flour and water, not a commercial glue.


Premium or limited-edition brands may also be individually numbered or even signed. Herradura's Seleccion Suprema, for example, is limited to a production run of 2,000 bottles.


Tequila bottles are no longer merely containers to hold your favourite elixir, then to be discarded. They have become a marketing tool, a work of art, and a collectors' item. They look exquisite on the mantle. There are buyers and sellers on eBay who deal in tequila bottles and the business seems to be thriving.




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