Harvesting & Processing
When yerba maté trees have reached 4 to 6 years old, they are ready to harvest. At this point, the cultivated trees are around 4 to 5 meters tall. The harvest occurs once every 2 years at the end of winter, in a rotating system, where only a section of the plantation is harvested at one time. This provides a constant supply of leaves by giving the maté trees 2 years to replace growth lost in the harvest. The native trees may be harvested at any time of the year, but only once every 3 to 4 years.
The workers that gather yerba maté leaves are from experienced families. They are trained to prune the trees the right way; a skill that has been passed down in these families through generations. Special care is applied so that the tree is not hurt during the harvest. Shortly after harvest the maté trees put forth new shoots, which becomes the growth harvested 2 years later.
Harvest time affects the flavour of the yerba maté, as well as its nutritional and stimulating properties. Maté leaves gathered in February and March tend to have a notably higher stimulating effect than that of the leaves gathered in September, but they also tend to be more bitter.
At the yerba maté processing plant, the branches are spread on a conveyor belt that carries them to the hopper, which is called in Portuguese, a “Sapecador” (Saw-pa-caw-door). From there, the branches fall through the leaping flames of a fire made by our proprietary Cleanheat System®. This means that the yerba maté leaves do not come in contact with the dense smoke of a traditional wood fire. This process heats the surface of the leaf to 400°C for fractions of a second, breaking a thin film of protective enzymes coating the surface of the leaf. These enzymes, peroxidase and polifenoloxidase would otherwise hinder the evaporation of the water content and cause oxidation in the leaves during the drying process, rendering the yerba maté useless. Microorganisms that could cause fermentation and further contaminate the product are also removed by the fire. This process does not overheat the inner part of the yerba maté leaf, leaving the nutritional properties intact.
The yerba maté leaves then roll through a spinning cylinder in which Cleanheat is blown, maintaining a controlled temperature to initiate dehydration. After leaving this first cylinder, the leaves are crushed to quicken the drying process. Crushed leaves then enter the dehydration cylinder, traveling back and forth three times while being blown with more warm air generated by our Cleanheat System. The temperature in this cylinder is lower than the previous one, ensuring the yerba maté leaves dry evenly.
After dehydration is complete the yerba maté leaves are cut, sifted, and blended to different specifications. We combine percentages of native and cultivated yerba maté to reach the desired flavour.
The maté then sits for at least 24 hours to let the rest of the humidity evaporate. After, it is packaged in 2.5kg triple layer bags where it can be maintained in a stable condition for more than two years, keeping intact the nutritional properties. The triple-layer packaging serves as a barrier to oxygen and light, the two main sources of oxidation.
Studies have shown that the properties of yerba maté suffer little variation during this process; the mineral percentage actually concentrates due to evaporation. Our Cleanheat System preserves the full nutrition of the original leaf.
Note: This description fits the yerba maté grown and processed by Maté Factor only and should not be considered fitting to describe processing or cultivating of yerba maté by other companies or groups.