Tequila is distilled from fermented juice of the agave (also known as maguey – pronounced muh-GAY) plant. Contrary to popular belief, the agave is a spiky-leafed member of the lily family – it is not a cactus. By Mexican law, Tequila can be made only from one particular type of agave, the blue agave (Agave Tequiliana Weber), and can be produced only in specifically designated geographic areas, primarily the state of Jalisco in west-central Mexico. Mezcal, a cousin of Tequila, is made from the fermented juice of other species of agave. It is produced throughout most of Mexico.

Though most tequilas are 80 proof, many distillers will distill to 100 proof and then cut it down with water to reduce its harshness. Some of the more well respected brands distill the alcohol to 80 proof without using additional water as a diluter.

There are two basic designations of Tequila, agave and mixto, arising from differences in the fermentation stage. Agave represents Tequila that is made only with agave juice and some water. Mixto means that the agave juice has been mixed with other sugars, usually sugar with water.

The four categories of Tequila (agave or mixto) are:

• Silver or Blanco/White Tequilas are clear, with little (no more than 60 days in stainless steel tanks) or no aging. They can be either 100% agave or mixto. Silver Tequilas are used primarily for mixing and blend particularly well into fruit-based drinks.

• Gold Tequila is unaged silver Tequila that has been colored and flavored with caramel. It is usually a mixto.

• Reposado ("rested") Tequila is aged in wooden tanks or casks for a legal minimum period of at least two months, with the better-quality brands spending three to nine months in wood. It can be either 100% agave or mixto. Reposado Tequilas are the best-selling Tequilas in Mexico.

• Añejo ("old") Tequila is aged in wooden barrels (usually old Bourbon barrels) for a minimum of 12 months. The best-quality anejos are aged 18 months to three years for mixtos, and up to four years for 100% agaves. Aging Tequila for more than four years is a matter of controversy. Most Tequila producers oppose doing so because they feel that "excessive" oak aging will overwhelm the distinctive earthy and vegetal agave flavor notes.

And to answer the question on everyone's mind…The famous "worm" that is found in some bottles of Mezcal is actually the larva of one of two moths that live on the agave plant. The reason for adding the worm to the bottle of Mezcal is obscure. A story that seems to make sense is that the worm serves as proof of high alcohol content: if the worm remains intact in the bottle, the percentage of alcohol in the spirit is high enough to preserve the pickled worm. However, most top-quality mezcals do not include a worm in the bottle.

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