The stalk is not allowed to grow on cultivated agaves, because it uses up the nutrients in the plant to produce its seeds, and is cut so the pi a grows fatter. The pi a is ripe when it starts to shrink and develops a maroon tinge, and red spots appear on the leaves. The skill of harvesting is passed down from father to son and some fields have three generations of jimadors working in them. Methodical, but efficient, a good jimador can harvest more than a ton of pi as in a day. The remainder of the agave has no other uses.
Harvesting is done year-round because the plants mature at different stages in the fields.
Some large distillers pick young agaves, but others, like Herradura, use only plants 10 years or older. S ome distillers will 'pre-cook' the pi as to rid them of external waxes and solids that may be retained in the penca. These can make a bitter or unpleasant juice. The steam-injected autoclaves used in modern distilleries also wash away any external materials from the pi as. Farmers who sell pi as by weight may leave on more of the penca, while those paid daily wages by the producer are more likely to cut them off closer to the pi a.