Alexis · Fondateur d'YVY Maté
Mate, South America's emblematic drink, is traditionally prepared from dried yerba mate leaves. Among the different drying methods, barbacuá is often highlighted for its authentic character and smoky aroma.
However, this technique can expose the yerba to potentially toxic compounds from burning wood. In this article, we take stock of Polycyclic Aromatic Hydrocarbons (PAHs), the existing studies, and the solutions that reduce the health risks.
What is the barbacuá method?
The "barbacuá" drying method exposes the yerba mate to - and thus dries it with - the smoke and heat of a wood fire for several hours, or even several days.
The goal of this drying technique is to dehydrate the leaves quickly while giving them a characteristic smoky taste.
Though regarded as ancestral know-how, this process brings the smoke into direct contact with the yerba, potentially releasing chemical compounds into the leaves - such as Polycyclic Aromatic Hydrocarbons (PAHs).
The barbacuá drying method
PAHs: compounds to watch closely
Polycyclic Aromatic Hydrocarbons (PAHs) are chemical substances that form when organic matter, such as wood or coal, burns incompletely. The combustion doesn't finish fully, producing residues as particles and gases.
A well-known example of these substances is benzo(a)pyrene. This compound has been the subject of many scientific studies, as it is recognized as hazardous to health. Several international organizations, including the International Agency for Research on Cancer (IARC), classify it among carcinogenic substances - that is, capable of causing cancers.
In the drying process called barbacuá, used notably to prepare yerba mate, the hot smoke in contact with the leaves deposits these combustion residues directly onto them. That's how PAHs can end up in the final product.
When the mate is prepared (with hot water), part of the PAHs stuck to the leaves can dissolve into the brew. Although the scale of this exposure varies with smoking time, wood type or the distance between flame and leaves, it's essential to keep in mind if you regularly drink smoked mate.
The potential dangers: what the studies say
Several epidemiological studies conducted in Argentina, Paraguay and Brazil suggest a link between very frequent consumption of smoked mate (often associated with barbacuá) and an increased risk of certain cancers (mouth, esophagus).
Worth noting: the studies also point to excessively hot brewing temperatures as an aggravating factor, but direct smoke introduces PAHs into the drink and can heighten these risks.
The World Health Organization (WHO) warns against drinking very hot beverages. In addition, various agencies - including the International Agency for Research on Cancer (IARC) - recognize PAHs as proven or probable carcinogens.
While these substances are regulated for certain smoked products (fish, cured meats), no equally strict international standards exist for mate. This lack of clear regulation makes it hard to guarantee low PAH levels across all barbacuá productions.
Polycyclic Aromatic Hydrocarbons (PAHs)
The alternative to barbacuá mate drying
More and more plantations are replacing or supplementing the traditional barbacuá method with modern processes designed to avoid direct contact between the yerba mate leaves and wood smoke.
Hot-air dryers (air-flow dryers)
Unlike barbacuá, where the leaves are exposed to wood-fire smoke, hot-air drying relies on indirect, better-regulated heat. Here are the main steps:
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Loading the leaves
The freshly harvested yerba mate is placed on a conveyor belt or in rotating drums inside a drying tunnel.
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Hot-air circulation
Hot air (from a boiler or a gas/electric heat source) is pushed or drawn through the tunnel, circulating around the leaves.
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Precise temperature and humidity control
The hot air extracts moisture from the leaves gradually, with no smoke produced in direct contact with the mate leaves.
Indirect hot-air drying avoids altering the leaves' aromas and quality.
Combustion, when it occurs, takes place in a separate compartment, and the resulting smoke is generally eliminated or diverted before reaching the leaves.
This method has several advantages: it eliminates PAHs by removing direct smoke contact, while allowing finer control of moisture levels and temperature.
This is precisely the drying technique our grower uses for drying our organic mate.
Modern mate drying
What are the advantages of hot-air drying?
PAHs reduced to near-zero levels
- Eliminates the risks tied to wood-smoke contact.
- Compliance with stricter health standards in Europe and elsewhere.
Preservation of mate's properties
- Better retention of nutrients (polyphenols, antioxidants).
- Maintains a "purer", fresher taste, without a heavy smoky aroma.
Precise quality control
- Fine humidity regulation, ensuring optimal shelf life.
- The leaves' flavor preserved.
- Less variation between production batches.
Reduced environmental impact
- Less pollution from burning wood.
- Some modern facilities use renewable energy to heat the air.
