Abstract: A process of controlling the blending of components to produce a product composition at a target value for least one characteristic has been developed. The process involves varying the proportion of the components, determining with each variation the change in the value of a characteristic, adjusting the proportion of those components to afford a new composition where the value of the characteristic is numerically closer to the target value, and repeating the steps until the target value of the characteristic is achieved. The process further includes determining blending factors to be used in existing blending equations.