Due to its size, this treatise on mezcal and other agave spirits is published in several parts, as follows:
- Part 1: Introduction, Aztec Mythology, the Agave
- Part 2: Pulque
- Part 3: Mezcal – history, legal requirements
- Part 4: Agaves, terroir, harvest, baking
- Part 5: Fermentation, distillation, maturation, the “worm”
- Part 6: Traditional manufacture and international corporations
- Part 7: Tequila – history and legal requirements
- Part 8. Tequila – Agave, terroir, harvesting, baking
- Part 9. Tequila – fermentation, distillation, maturation, additives
- Part 10. Sustainability
- Part 11. Bacanora, Raicilla, Sikua, Sotol, Destillado de Agave
Today, the fermentation containers are mostly made of stainless steel; in the past, they were made of wood. Some say that wood improves the fermentation and gives richer flavours. The Tequila Regulatory Council, on the other hand, advises against wooden containers for hygienic reasons, because steel is easier to clean. [2-54] [2-60]
Tequila is distilled differently than mezcal. The latter is distilled in batches and in small copper or clay pot stills. Tequila, on the other hand, is mainly distilled continuously in an industrialised process using the column distillation method in huge columns. [1-45] 
Nevertheless, tequila is required to be distilled twice. However, it is difficult to prove that it has been distilled twice using the column distillation method, which is why the pot still method is often used in addition. [2-25]    Tequila is also distilled more than twice, but as with any other spirit, this does not necessarily make the distillate better, because the purer a distillate becomes, the more it loses character and aroma. [2-25] 
Tequila is produced in large quantities. This is only possible with industrial, automated processes. Additives are also used, not only to increase efficiency, but also to enable consistent quality. One bottle should taste like the other. But this also means that none of these tequilas are still produced in the same way as Mezcal. Due to the industrialised, automated and uniform production methods, much of the distiller’s handwriting is lost. [2-26] [2-95] And so there are producers who give preference to traditional methods, and among these producers modern technologies are not so all-encompassing. [2-26] But most traditional methods are not required by law. [2-60]
Tequila is differentiated into
- Blanco or plata, which translates as “white” or “silver”. This tequila is unaged and less than 60 days old. It can be bottled directly from distillation or can be stored temporarily in steel tanks. Sometimes it is also stored in large oak barrels, but this may only be done for a maximum of 30 days. [2-xvii]     
- Joven, (also joven abocado), also called oro, which translates as “young” or “gold”, is a category for mixtos, i.e. tequilas made from at least 51% agave and up to 49% other sugar sources. Such a tequila is basically the same as a blanco, but with colouring and flavouring added. It is usually coloured by the addition of caramel or oak essence, with up to 1% by weight.   
- Reposado, which translates as “aged”, is aged for two months to a year in oak barrels that hold up to 20 000 litres. More than 60% of the tequila sold in Mexico is a reposado. Most producers age it in oak barrels, preferably American, French or Canadian, but other barrels are also used, for example red wine barrels. Some producers use new barrels. [2-xviii]      
- Anejo, which translates as “old”, is aged in sealed barrels of no more than 600 litres, usually around 200 litres, for at least one year. It may also be matured for longer, even up to ten years. It can be taken out of the barrels after four years and transferred to steel barrels. Normally, it is stored in oak barrels like a Reposado. New barrels are hardly ever used because they give off wood aromas too quickly. [1-51] [2-xviii]    
- Extra Anejo, which translates as “extra old”, has been permitted since 2006, and has been aged for at least three years in barrels that hold a maximum of 600 litres, but normally hold a volume of less than 200 litres. [2-xix]    
The storage takes place in barrels sealed by the CRT (Consejo Regulado de Tequila). 
The Añejo Tequila is said to have originated around 1800. The company “José Cuervo” claims to have been the first to bring it to market in that year. It was inspired by wealthy Mexicans who enjoyed matured spirits such as whiskey or brandy. One might think that the Reposado is older than the Añejo, but that is not the case. The Reposado only came onto the market in 1974. The Herradura company claims to have been the first to develop the Reposado, in response to a product launched by Cuervo. Cuervo wanted to colour a Blanco Tequila with sugar caramel for the American market, where dark spirits were preferred. This embarrassed Herradura, because they were of the opinion that colouring had to be done by barrel ageing. So both companies made submissions to the Mexican authorities. [1-137] [2-xviii] [2-16]  As a result, Cuervo was allowed to market a coloured tequila with the designation joven or oro, as it is still prescribed today. At the same time, Herradura was allowed to market a barrel-aged reposado. Today, 80% of the tequila drunk in Mexico is a reposado, and so it seems strange that Herradura was not initially thought to be successful with her idea, since high financial expenditures were necessary for the purchase of barrels and storage space, and the maturing process also took a lot of time. However, it is important to know that at that time most tequilas were sold unaged, the Añejo was not popular. [2-xix]
Tequila was bottled for the first time in 1906, by the Cuervo company. 
Further types and additives
Beyond the types mentioned in the last chapter, others are available on the market. For example, some producers started filtering matured tequila to remove the colouring caused by barrel ageing. Tequila also comes in different flavours, such as strawberry, citrus, chocolate or jalapeño. Additives are allowed and used to adjust the colour, aroma and texture of the tequila: sugar caramel is used to darken the spirit, oak extract to simulate barrel ageing, glycerine to adjust the texture and sugar syrup to sweeten. However, it is mandatory that the addition of such additives be listed on the label. [2-xix] [2-xx] [2-72] 
- John McEvoy: Holy Smoke! It’s Mezcal. ISBN 978-0-9903281-0-0. Mezcal PhD Publishing, 2014.
- Chantal Martineau: How the Gringos Stole Tequila. The Modern Age of Mexico’s Most Traditional Spirit. ISBN 978-1-61374-905-0. Chicago, Chicago Review Press, 2015.
- http://www.ianchadwick.com/tequila/fermentation.htm: Fermentation.
- http://www.ianchadwick.com/tequila/distillation.htm: Tequila Distillation.
- http://www.ianchadwick.com/tequila/laws.htm: Laws and Regulations for Tequila.
- http://www.ianchadwick.com/tequila/aging.htm: How Tequila is Aged & Bottled.
- http://www.ianchadwick.com/tequila/types.htm: The five types of tequila.
- http://www.ianchadwick.com/tequila/mezcal_denomination.htm: Mezcal’s Denomination of Origin.
- Bastian Heuser: Tequila – Die Fakten. Mixology 2/2008, page 72.
- Jürgen Deibel: Tequila-Produktion. Mixology 3/2008, page 68-70.
- Anonymus: Victoria Bar. Die Schule der Trunkenheit. Therein: Sechstes Semester. Der Tequila. ISBN 978-3-8493-0323-5. Berlin, Merolit Verlag, 2013.
- http://www.ianchadwick.com/tequila/18-19th%20centuries.htm: Tequila’s History. Part 2 of 3. 18th & 19th Centuries.
- http://www.ianchadwick.com/tequila/20-21st%20centuries.htm: Tequila’s History. Part 3 of 3. 20th & 21st Centuries.
- https://commons.wikimedia.org/wiki/File:Tequila-barrel.JPG: Tequila-Fässer in der Tequila-Fabrik von “El Jimador” in der Nähe von Tequila, Jalisco.