Final answer:
The milled and mashed agave is slow-cooked to convert complex carbohydrates into fermentable sugars, crucial for the fermentation process in tequila production.
Step-by-step explanation:
Before fermentation, the milled and mashed agave is slow-cooked over moderate heat primarily to convert the inulin polymer into fermentable fructose and glucose. This is a necessary step in tequila production because agave plants contain inulin, a complex carbohydrate that must be broken down into fermentable sugars before yeast can use it in the fermentation process. This slow cooking also can contribute to the flavor profile of the tequila but does not itself start the fermentation process or pre-ferment to an alcohol level of 2. The smoky taste often associated with some types of tequila is more typically imparted during a different part of the process, such as through the type of oven used or through the distillation process for mezcal, where the plants are often cooked in pit ovens.