What Exactly Is Stevia? Ask Paul

It also makes sense that in post-industrial life, when many people seek to eat fewer calories rather than more, non-nutritive sweeteners such as stevia—i.e. ingredients that sweeten without calories—are on the rise.

Stevia comes from the shrub Stevia rebaudiana native to Paraguay, where its leaves have been used for centuries to sweeten beverages. In the 20th century, the active chemical ingredients in the plant—a family of compounds called steviol glycosides— were isolated. These molecules stimulate sweet receptors in our taste buds, and simultaneously increase the activity of certain neural channels that carry taste signals, known as TRPM5.

Because the glycosides are essentially able to intensify their own sweet-tasting effect on our tongues, they taste much sweeter than sugar does—the most common glycoside used in stevia products, rebaudioside A, tastes about 300 times sweeter than white sugar.

Although the FDA has not approved stevia leaf for use in food products, purified rebaudioside A extracted from the plant is generally recognized as safe, and widely used for sweetening as a standalone product and in processed foods.

Nobody has yet figured out an alternative to sugar that tastes exactly the same. Stevia extracts, for example, have a slight licorice-y flavor as well as a little bitterness; their sweetness also lingers longer than sugar. Some manufacturers blend stevia with sugar as well as other alternative sweeteners in an attempt to create a closer facsimile. But they haven’t hit on a perfect solution yet.

In addition to not tasting exactly like sugar, stevia does not behave like sugar. 

One challenge is its sheer sweetening power. If you put a spoonful of pure stevia extract in your iced tea, it would be 300 times sweeter than tea sweetened with a spoonful of sugar. So stevia products sold for home use are typically diluted: 1 part stevia to 299 parts of another powder or liquid that allows them to be substituted one-for-one with a comparable level of sweetness.

Stevia also doesn’t share the same properties as sugar.  For example, when we bake with sugar, it is a central part of the texture of the baked good, holding and releasing water in certain dependable ways, providing chew, crunch, and structure.

Some stevia products have been formulated to emulate the functional behavior of sugar in baking—usually by combining it with an ingredient such as maltodextrin that behaves similarly (not identically) to sugar when baked. But results may vary. 

In short, stevia (and all the other non-nutritive sweeteners) can take the place of sugar for some, but not nearly all, applications.