Native to South America and grown in other tropical and sub-tropical regions of the world, Stevia is an herb cultivated for its leaves that contain an extract that is exponentially sweeter than sugar.
Ancient Origins of Stevia
Evidence indicates that Stevia was first used by the Guarani and Mato Grosso Indian tribes who lived in the region of modern-day Paraguay. For many centuries, these natives utilized the leaves of the Stevia plant as a sweetening agent for various bitter teas, as well as for medicinal concoctions. In the 1500s, the Spanish Conquistadors learned of Stevia’s sweetening properties from the Indians. Over the next few hundred years, the use of Stevia had spread to other parts of South America and Mexico. European travelers were taking a keen interest in the herb and began taking samples of it overseas to learn how to cultivate it and to study its properties.
By the 1930s, many countries, including Spain, Switzerland and France, were researching Stevia as an alternative to sugar. In the 1970s, it was Japan that was the first to successfully market Stevia as a sugar substitute.
Cultivation of Stevia
Stevia can be grown in a wide variety of soils and can tolerate a fairly wide range of pH levels. Ideally, though, it grows best in sandy loam type soil and, in the wild, the pH level is slightly acidic. The herb is best grown under moist conditions. Too much water, however, will cause the roots to rot. Growing from seed is not recommended. Home gardeners are much more successful with transplants or cuttings, which can be obtained from herb farms, mail order or internet sources. Planting transplants in the garden should be done only after all danger of frost has passed. Partial shade is recommended for extremely hot and sunny areas. Stevia also grows well in containers.
Harvesting Stevia Leaves
The Stevia plant is coveted for its sweet compounds, called Steviosides. There are varying amounts of Stevioside concentrations in all parts of the plant but the greatest concentration is contained in the leaves. Harvesting the leaves, which is done in the fall, is a simple process that consists of simply stripping the green leaves from the stem and allowing them to dry in the sun for about 12 hours. Old, brown leaves can be used as well; however, the Stevioside concentration in them is somewhat diminished. When the leaves are thoroughly dry, they can be stored in a plastic bag or container away from moisture. To make a dissolvable powder that can be used in coffee or tea, place leaves in a food processor or blender and process thoroughly. Store processed leaves in an airtight container.
References: "The Stevia Story: A Tale of Incredible Sweetness & Intrigue"; Donna Gates; 2000