The SRM number was originally, and still is, defined by "Beer color intensity on a sample free of turbidity and having the spectral characteristics of an average beer is 10 times the absorbance of the beer measured in a 1/2-inch cell with monochromatic light at 430 nanometers." Modern spectrophotometers use 1 cm cuvettes rather than 1/2 inch ones. When a 1 cm cuvette is used, application of the Bouguer-Beer-Lambert law shows that the multiplier should be 12.7 rather than 10. When the SRM value for a beer or wort is larger than about 30 the log linear limit of some instruments using 1 cm cuvettes is approached. In such cases the sample is diluted with deionized water. Using Beer-Lambert again gives the mathematical definition of SRM in the general case as: