Milva Ayala is surprised to learn that in European cafés it has become common to find stevia sachets to sweeten drinks: “How wonderful it would be if it were like that here too!” On the outskirts of Ciudad del Este, Paraguay, she and her husband clear their field of ka’a he’e, or “sweet grass” in Guaraní, the name by which stevia is known here, their country of origin. It was the Guaraní indigenous people who discovered the sweetening properties of this plant, known only to them until just over a century ago. Today, when its consumption is global, producers in places as far away as China and Thailand benefit from its commercial exploitation. On the other hand, in the South American country, farmers like Ayala are struggling to ride a wave that already generates almost a billion dollars in global sales, a figure that will double in the next 10 years, according to the consultancy firm Expert Market Research.
“I grew up growing ka’a he’e. My family, the Gonzálezes, participated in the domestication of the plant,” says Walter González, Ayala’s husband. “But we left it because there was no one interested in buying it.” Stevia began to be cultivated commercially in 1964, six decades after Swiss scientist Moisés Bertoni first classified it. Shortly thereafter, Japanese researchers exploited the seeds to develop more profitable varieties, such as Morita, with which they managed to produce the first stevia sweetener in 1971.
Since then, plantations have spread throughout Asia, Europe, Africa and other countries in the Americas. In 2023, Thailand has replaced China as the top exporter, with France, the Netherlands and the United States in third, fourth and fifth place, according to Tridge data. Paraguay is not in the list of the 10 largest exporters. The South American country has lagged behind in the exploitation of its native plant, leading farmers, like the González, to abandon the sector. “Those who used to plant ka’a now grow sesame, corn or beans,” explains Walter González. “Some plant a little for themselves, but for a larger plantation there would have to be a very serious demand.”
He believes he found her through Margarita Duarte. “There was a time when stevia production was highly promoted, but there was no market, so people were disappointed that they couldn’t sell and stopped planting. But today there is a huge market,” says Duarte, an exporter of stevia leaves and owner of the tea and infusion factory Py Teas. “What is missing is to increase production, but with quality.”
Paraguay failed to take advantage of the stevia boom. The value of its exports fell 22% in 2024 to $333,000, according to data from the state export promotion agency, Rediex. The flight of disappointed producers, in addition to the effects of the pandemic and the drought that the country has suffered since 2020, are important factors in this reduction, but in the end, the contraction of purchases from China is what has caused exports to collapse by 87% since 2017. Duarte adds another obstacle: “The quality that Europeans demand is organic and here the producer is used to working with conventional plants,” he explains. “You need certifications and a lot of technical assistance. The producer needs an irrigation system, inputs, tools and organic fertilizers. He needs to be taught how to make his nursery, how to cut the seedlings and all this has a cost.”
Milva Ayala and her husband have experienced these difficulties firsthand. “We wanted to try Morita, the improved ka’a he’e variety, and we lost. We bought it because its leaves are sweeter, but it needed an irrigation system and simple people like us can’t afford it,” he recalls as he drinks a cold mate or tereré to relieve the heat. “The native variety, on the other hand, can last a month without rain.”
But the obstacles to the Paraguayan stevia industry are not only on the ground. Entrepreneurs like Duarte work with this plant, but without engaging in the sweetener sector. They prefer to do business with other uses of ka’a he’e, such as their signature infusions, Py Teas, which combine it with yerba mate or green tea. Duarte also exports stevia leaves, but to European customers who use them to make teas.
Luis Ernesto Zillich, another Paraguayan businessman in the stevia industry, also ruled out sweeteners. “Do you know that we have very strong competitors like China or Malaysia?” he asks. “We cannot compete with the price at which the leaves are sold in China.” Zillich admits that when his father started working with stevia in 1995, he also had sweeteners in mind. “But for a sweetener to be accepted, it is necessary to discard the entire contents of the plant and concentrate its sweet active ingredients, which are stevioside and rebaudioside A. It must be concentrated to a purity of 95%,” he explains. “In the end, what I really got was a tea, a stevia tea mixed with black tea and lemon verbena.” Today his company, Stevia Natural, has chosen to produce stevia-based fertilizers and medicines. One of these is Berdiana, a tablet to regulate blood sugar in patients with diabetes. “We decided not to get involved in the sweetener because there was a lot of competition,” he says.
a good time
The person who chose to produce the stevia sweetener in Paraguay is the Argentine biochemical engineer Alejandro Aguirre, who, together with Canadian partners, set up a factory in Ypacaraí, an hour from the Paraguayan capital Asunción. “It’s a factory that collapsed due to low Chinese prices. But now we’ve recovered it and we have great demand,” he explains. For Aguirre, this is a good time to promote the ka’a he’e industry: “China supplies the United States with between 80% and 90% of the stevia it uses. The large tariffs that the United States has imposed on China have pushed customers to look to other markets, such as Paraguay. With this change alone we calculate that demand has grown between 20% and 25%.”
The benefits, however, will not be short-term. “There will be a boom, but because agriculture is slow, I don’t think it will happen now, but in a year and a half or two, because everything is just starting to be replanted with stevia,” Aguirre says. Although people from different latitudes sweeten their coffee with a plant discovered by the Guaraní, few associate Paraguay with stevia. “To the extent that they become a little more familiar with Paraguay as a source of stevia, the demand will certainly increase even more,” concludes Aguirre.
