Editing Tequila (section)

=== Alcohol content ===
[[File:S cerevisiae under DIC microscopy.jpg|thumb|''[[Saccharomyces cerevisiae]]'', under a microscope]]
Tequila must have between 35% and 55% alcohol content (70 and 110 U.S. proof).<ref name="tequila.net">{{cite web | url = http://www.tequila.net/faqs/tequila/what-are-the-regulations-governing-tequila.html#chapter6 | title = Official Mexican Standard for Tequila | access-date = 2010-07-13 | archive-date = 2013-10-30 | archive-url = https://web.archive.org/web/20131030034521/http://www.tequila.net/faqs/tequila/what-are-the-regulations-governing-tequila.html#chapter6 | url-status = live }}</ref> Tequila is a distilled beverage that is made from the fermentation of the sugars in the blue agave plant once it has been cooked, the main sugar being fructose.<ref name="Pinal">{{Cite journal|last1=Pinal|first1=Leticia|last2=Cedeño|first2=Miguel|last3=Gutiérrez|first3=Humberto|last4=Alvarez-Jacobs|first4=Jaime|date=1997-01-01|title=Fermentation parameters influencing higher alcohol production in the tequila process|journal=Biotechnology Letters|language=en|volume=19|issue=1|pages=45–47|doi=10.1023/A:1018362919846|s2cid=40739267|issn=0141-5492}}</ref> Through the fermentation process, many factors influence the higher-order alcohols present in tequila, which include molecules such as [[Isobutanol|isobutyl alcohol]] and [[isoamyl alcohol]], along with the [[ethanol]].<ref name="Pinal" /> Factors include the strain of yeast, the age of the agave plant itself, temperature, and the ratio of carbon to nitrogen.

The yeast strain used and the carbon-to-nitrogen ratio have the biggest influence on the production of higher-order alcohols; this is not surprising, as production of ethanol and higher-order alcohols is an intrinsic property of the metabolism of each strain.<ref name="Pinal" /> The type of yeast most commonly found in tequila is ''[[Saccharomyces cerevisiae]]'', which can include many different strains. For example, ''CF1 agaves'', a type of yeast, produces much more ethanol than a CF2 strain, as the two yeasts' metabolic mechanisms differ.<ref name="Pinal" /> Prevalence of certain strains of yeast may be influenced by agricultural practices. It was found that higher ratios of carbon to nitrogen resulted in greater production of higher-order alcohols such as isobutyl alcohol and isoamyl alcohol. The lower level of nitrogen in the fermentation process results in deamination reactions of [[amino acid]]s, which in turn leads to the synthesis of higher alcohols.<ref name="Pinal" /> The [[Ehrlich pathway]] refers to this process in which alpha-keto acids are decarboxylated and transformed to aldehydes and to higher alcohols.

The temperature of the fermentation process also greatly affects the alcohol content of the resulting product. For example, a study conducted by Pinal ''et al.'' found that cultivating two strains at a temperature of 35&nbsp;°C as compared to a temperature of 30&nbsp;°C produced more isoamyl alcohol. The higher temperature appears to be favorable for the action of the yeast.<ref name="Pinal" />

The age of the agave plant is also a factor: the older the plant, the greater the production of higher-order alcohols. It was shown in a study that the concentration of amyl alcohol increased by 30% as the plant aged. Conversely, a higher concentration of methanol is found when using younger plants. This change may be due to differences in agricultural practices with plants of different ages.