Yerba Mate Processing - A Beginner's Guide

Yerba Mate, the South American herb, is becoming more and more popular in the UK, perhaps for its weight-loss properties.  But have you ever wondered how the raw herb is processed?

Yerba mate is still plucked by hand on most plantations.  Though mechanisation is increasing, selecting the best leaves from the tree is a skill that takes some time to learn and it is not easy for a machine to be as accurate.

Processing, on the other hand, is pretty much mechanised.  Most mate growing regions have a processing facility that is shared by several small growers.  This is important as the leaves must be processed within 24 hours of harvesting.

Exact details of processing vary from one plantation to another, and these are often a closely-guarded secret.  But the basic steps, as described here, remain the same.

Six stages of processing

1. Sapecado.

Within 24 hours of plucking the mate leaves are flash-dried to de-nature the enzymes and prevent oxidation of the leaves.

2. Secado.

A second and third drying stage then usually occur.  These are increasingly long and gentle and by the end of the third drying the leaves have a moisture content of about 8%.  The Guaraní Indians had two distinct methods for this stage – one, carijó, used direct heat, and the other, barbacuá, smoked the leaves.

3. Canchado.

The dry leaves are passed through a roller to grind them and break them into small pieces. Twigs are removed at this point as necessary, depending on required quality.

4. Beneficio.

A long, slow fermentation now takes place.   This lasts for at least 6 months and possibly as long as 12 months, if done naturally.  Nowadays, forced fermentation using hot air is becoming increasingly popular.  This produces fermented mate within 4 - 6 weeks.

5. Tostado.

If roasted mate is required the roasting occurs at this stage.

6. Grinding

Finally the mate is ground, graded by size and quality, blended (possibly with herbs, flavourings, dried fruit or other types of tea) and packed.

Grades of Yerba Mate

  • Canchada. Ground.  Ordinary mate.
  • Elaborada con palo. Processed, with twigs.  Less than 35% stalks.
  • Despalillada. De-twigged.   Less than 10% stalks.
  • Tostada. Roasted.  Stage 5 above.

So there you have it in a nutshell.  Yerba Mate is delicious and healthy, so if you've never tried it, now's the time.  Meanwhile there are a few more articles on this blog that explain how to drink it, and some of its health-giving properties.