How is Sweetness Measured?
by D. Eric Walters, Ph.D.
The "Percent Sucrose Equivalent" scale
Sweetness is commonly measured by comparison to reference solutions of sucrose. Sucrose is the standard to which all other sweeteners are compared. Humans can recognize sweetness in about 1 or 2% sucrose solution. Coffee is typically sweetened to about the level of 5% sucrose. Soft drinks are usually about as sweet as 10% sucrose. 15% sucrose is really sweet and starts to feel a little syrupy. Taste panelists are often trained to quantitate sweetness on a 15 cm line scale, for convenience, using 2-15% sucrose solutions as references.
Other sweeteners are then tasted at a series of dilutions to determine the concentration that is as sweet as a given percent sucrose reference. For example, if a 1% solution of sweetener X is as sweet as a 10% sucrose solution, then sweetener X is said to be 10 times as potent as sucrose.
For a detailed discussion, see "A Systematic Study of Concentration-Response Relationships of Sweeteners," G.E. DuBois, D.E. Walters, S.S. Schiffman, Z.S. Warwick, B.J. Booth, S.D. Pecore, K. Gibes, B.T. Carr, and L.M. Brands, in Sweeteners: Discovery, Molecular Design and Chemoreception, D.E. Walters, F.T. Orthoefer, and G.E. DuBois, Eds., American Chemical Society, Washington, DC (1991), pp 261-276.