late or too early, the piñas, which can average around in the valley to in the highlands, will not have the right amount of carbohydrates for fermentation. After harvesting, the piñas are transported to ovens where they are slowly baked to break down their complex fructans into simple fructose. Then, the baked piñas are either shredded or mashed under a large stone wheel called a tahona . The pulp fiber, or bagazo , left behind is often reused as compost or animal feed, but can even be burnt as fuel or processed into paper. Some producers like to add a small amount of bagazo back into their fermentation tanks for a stronger agave flavor in the final product. The extracted agave juice is then poured into either large wooden or stainless steel vats for several days to ferment, resulting in a wort, or mosto , with low alcohol content. This wort is then distilled once to produce what is called ordinario , and then a second time to produce clear "silver" tequila. Using at least two distillations is required by law. A few producers such as Casa Noble (for their "Crystal" expression) and Corzo (for their añejo expression) have experimented with distilling the product a third time, but this has not caught on as a trend, and some have said it removes too much of the agave flavor from the tequila. From there, the tequila is either bottled as silver tequila, or it is pumped into wooden barrels to age, where it develops a mellower flavor and amber color. The differences in taste between tequila made from valley and highland agave plants can be noticeable. Plants grown in the highlands often yield sweeter and fruitier-tasting tequila, while valley agaves give the tequila an earthier flavor. Fermentation Unlike other tequila production steps, fermentation is one of the few steps out of the control of human beings. Fermentation is the conversion of sugars and carbohydrates to alcohol through yeast in anaerobic conditions, meaning that oxygen is not present during the process. Fermentation is also carried out in a non-aseptic environment which increases the bacterial activity of tequila. The participation of microorganisms from the environment (yeasts and bacteria) makes fermentation a spontaneous process which gives rise to many byproducts that contribute to the flavor and aroma of tequila. During the fermentation process, inoculum is added to the batch to speed the rate of