Appears in
Oxford Companion to Sugar and Sweets

By Darra Goldstein

Published 2015

  • About

saccharimeter is a scientific instrument used for sugar analysis that evolved from the simpler polariscope used by the French savant Jean-Baptiste Biot (1774–1862). From his experiments in light reflection in the second decade of the nineteenth century, Biot found that when he passed polarized light through some substances, the plane of polarization would rotate. He also found that cane sugar and beet sugar act the same in this regard, while other substances do not. Thus, a polariscope would enable him to distinguish sucrose from other sugars (such as glucose) that rotate the plane of polarization in the opposite direction. When Biot found that the strength of the sugar solution determines the extent of optical rotation, he realized that a polarimeter (a polariscope that measures this rotation) could be used to determine the quality of sugar for commercial or tax purposes. In the 1840s a French optical instrument maker named Jean-Baptiste François Soleil designed a polarimeter specifically for sugar analysis and termed it a saccharimeter. As subsequent improvements made saccharimeters more reliable and user friendly, these optical instruments came into widespread use in countries around the world.