Inverted or invert sugar syrup is a sucrose-based syrup, produced by splitting each sucrose disaccharide molecule into its component monomers, glucose and fructose. The splitting is achieved through the action of invertase (a glycoside hydrolase enzyme), or an acid. Comparing solutions with the same dissolved weight of sugar, inverted syrups are sweeter than sucrose solutions; at equal molar concentrations, inverted sugar syrup has only 85% the sweetness of sucrose solution but complete inversion of a solution of a disaccharide (such as sucrose) doubles the concentration of sugar molecules - this makes the resulting, inverted, syrup sweeter than the original sucrose solution. The glucose present in inverted sugar syrup is substantially more hygroscopic than sucrose. This means that the syrup tends to keep products made with it moist for longer than when sucrose is used alone. It is likewise less prone to crystallisation and therefore valued especially by bakers, who refer to inverted sugar syrup as 'trimoline' or 'invert syrup'. The term 'inverted' is derived from the method of measuring the concentration of sugar syrup using a polarimeter. Plane-polarized light, when passed through a sample of pure sucrose solution, is rotated to the right (optical rotation). As the solution is converted to a mixture of sucrose, fructose and glucose, the amount of rotation is reduced until (in a fully converted solution) the direction of rotation has changed (inverted) from right to left.