Stevia, derived from the leaves of the Stevia rebaudiana plant, contains steviol glycosides, sweet-tasting compounds that provide a natural, zero-calorie alternative to sugar. Many commercially available stevia products undergo extensive processing or are blended with fillers like dextrose and erythritol, leading some to seek a purer, homemade extract. Preparing the extract at home provides control over the final ingredients and allows for a more cost-effective way to utilize the plant’s sweetness. The process involves simple kitchen techniques to draw the sweet glycosides from the leaves into a liquid solvent.
Preparing Stevia Leaves for Extraction
Preparation begins with the leaves, whether freshly harvested or purchased dried. Stevia leaves contain the highest concentration of sweet compounds just before the plant begins to flower, making this the optimal time for harvest. If using fresh leaves, they must be thoroughly washed and dried until brittle. This drying step, which can be done by air-drying or using a food dehydrator on a low setting, concentrates the steviol glycosides and maximizes extraction efficiency.
Once dried, the leaves should be coarsely crushed or chopped to increase the surface area exposed to the solvent. Using a mortar and pestle or crumbling the leaves between your fingers works well. Avoid grinding the leaves into a fine powder, as fine particles are difficult to filter out later and can leave sediment in the finished extract.
Choosing and Executing the Extraction Method
The choice of solvent determines the concentration, shelf life, and flavor profile of the finished product, with two primary methods available: water-based and alcohol-based. A hot water extraction is the simplest approach, best suited for an extract that will be used immediately or within a short period. For this method, use a ratio of approximately one-half cup of lightly crushed dried leaves to one cup of near-boiling water. The leaves are steeped in the hot water for about 40 to 60 minutes. Water generally produces a less potent extract that must be refrigerated and used within one to two weeks.
The alcohol method, typically using a neutral spirit like vodka, yields a more concentrated and shelf-stable liquid due to alcohol’s superior ability to dissolve a wider range of the steviol glycosides. For this process, loosely fill a glass jar with crushed leaves and pour enough alcohol to fully submerge them. The mixture is sealed and allowed to steep for 24 to 48 hours. Steeping for too long, exceeding 48 hours, will begin to pull out bitter-tasting compounds, leading to an undesirable aftertaste. This short steeping time is a deliberate technique to favor the extraction of the sweet Rebaudioside A and Stevioside molecules while minimizing the less palatable plant components.
Finishing and Storing Homemade Stevia Extract
After the steeping period, the first step in finishing the extract is to separate the liquid from the spent leaf material. This is accomplished by pouring the mixture through a fine-mesh sieve lined with several layers of cheesecloth, a nut milk bag, or a paper coffee filter. For the clearest extract, a second filtration through a fresh coffee filter may be necessary to remove any remaining fine particles that can cloud the liquid.
The resulting liquid extract can then be concentrated to increase its sweetness and potency. For alcohol-based extracts, pour the strained liquid into a small saucepan and gently simmer it over low heat for 20 to 30 minutes. This process allows the alcohol to evaporate, which both concentrates the steviol glycosides and results in a non-alcoholic product, but it is important not to let the liquid boil, as excessive heat can damage the sweet compounds. Water-based extracts can also be reduced in a similar manner to decrease the volume and intensify the flavor.
The finished, concentrated extract should be allowed to cool completely before being transferred to a clean, airtight glass container, such as a small dropper bottle. Water-based and reduced alcohol extracts require refrigeration and will maintain quality for up to three months. When using the homemade extract, begin with a very small amount, such as two or three drops per serving, and adjust according to taste, as the concentration will vary significantly compared to commercial products.