Once the agave plants are mature, the harvesting process begins, traditionally known as la jima. Harvesting remains a manual effort, unchanged by modern farming technologies. The men who harvest the agaves -"jimadores"- posses the generations of knowledge that allows them to evaluate the maturity of each blue agave and harvest it when the concentration of the flavorful sugars has reached its peak.
Due to the long growing cycle, each agave represents an influence of the whole epoch of time - not just a single season. Blue agave generally reaches maturity in the plant’s 8th or 9th year of life, but it can take as long as 12 years in the high elevations of Los Altos. However, not all agaves planted at the same time will mature in the same year. As a result, the plantation is generally harvested out during 4 consecutive years and jimadores keep returning to the field seeking out and harvesting the mature plants. Because of this, tequila has no vintage where one year of production is better than another, as we often see in wine.
To produce premium tequilas, the ripened agaves are hand-selected and manually harvested. Mature piña can weigh 80 to 220 pounds and is spotted with red blotches around the stubs (called sangre – or blood), which indicates ripeness and a good balance of sugar and acidity. Harvested at its prime, such agaves result in flavorful, full-bodied tequila with complex taste and aroma. If the agave is harvested too early the sugar content will be poor, resulting in a product of inferior taste and flavor; and if the plant is allowed to ripe for too long, the agave will have produced a quiote – a flowering stem, which consumes all the sugars. After it happens, the agave plant is no longer good for tequila production.
To harvest the piña, the jimador cuts the plant loose from its roots and removes the spiky leaves from the piña with a special razor-sharp tool called a coa. The resulting piña resembles a gigantic white-and-green pineapple. A skilled jimador averages 50 to 60 piñas in a day’s work. The agave hearts are then loaded up on a truck and transported to a distillery for processing. It takes about 17 pounds of agave piña to produce 1 liter of 100% Blue Agave tequila.
The best results are achieved when the harvesting is done by selecting the agaves that are ripe versus harvesting them by field at the same time. That's why the year of harvest, displayed on some tequila labels, is simply a marketing ploy.
Trying to cut the costs, many producers harvest agaves by field when the plants are just 5 years old despite the fact that the pinas are small and lack sugars. The resulting tequila will be of inferior taste and flavor.