While going through my copy of Physically Based Rendering for the millionth time, I remembered that there is a nice utility function called GetVolumeScatteringProperties(). This function has access to a nice library of measured data from previous papers. The valid names are listed in core/volume.cpp, but for easier lookup they are also listed below.
// From "A Practical Model for Subsurface Light Transport"
// Jensen, Marschner, Levoy, Hanrahan
// Proc SIGGRAPH 2001
{ "Apple", { 2.29, 2.39, 1.97 }, { 0.0030, 0.0034, 0.046 }, },
{ "Chicken1", { 0.15, 0.21, 0.38 }, { 0.015, 0.077, 0.19 }, },
{ "Chicken2", { 0.19, 0.25, 0.32 }, { 0.018, 0.088, 0.20 }, },
{ "Cream", { 7.38, 5.47, 3.15 }, { 0.0002, 0.0028, 0.0163 }, },
{ "Ketchup", { 0.18, 0.07, 0.03 }, { 0.061, 0.97, 1.45 }, },
{ "Marble", { 2.19, 2.62, 3.00 }, { 0.0021, 0.0041, 0.0071 }, },
{ "Potato", { 0.68, 0.70, 0.55 }, { 0.0024, 0.0090, 0.12 }, },
{ "Skimmilk", { 0.70, 1.22, 1.90 }, { 0.0014, 0.0025, 0.0142 }, },
{ "Skin1", { 0.74, 0.88, 1.01 }, { 0.032, 0.17, 0.48 }, },
{ "Skin2", { 1.09, 1.59, 1.79 }, { 0.013, 0.070, 0.145 }, },
{ "Spectralon", { 11.6, 20.4, 14.9 }, { 0.00, 0.00, 0.00 }, },
{ "Wholemilk", { 2.55, 3.21, 3.77 }, { 0.0011, 0.0024, 0.014 }, },
// From "Acquiring Scattering Properties of Participating Media by Dilution", // Narasimhan, Gupta, Donner, Ramamoorthi, Nayar, Jensen // Proc SIGGRAPH 2006 { "Lowfat Milk", { 0.912600, 1.074800, 1.250000 }, { 0.000200, 0.000400, 0.000800 } }, { "Reduced Milk", { 1.075000, 1.221300, 1.394100 }, { 0.000200, 0.000400, 0.001000 } }, { "Regular Milk", { 1.187400, 1.329600, 1.460200 }, { 0.000100, 0.000300, 0.001300 } }, { "Espresso", { 0.437600, 0.511500, 0.604800 }, { 0.166900, 0.228700, 0.307800 } }, { "Mint Mocha Coffee", { 0.190000, 0.260000, 0.350000 }, { 0.098400, 0.151900, 0.204000 } }, { "Lowfat Soy Milk", { 0.141900, 0.162500, 0.274000 }, { 0.000100, 0.000500, 0.002500 } }, { "Regular Soy Milk", { 0.243400, 0.271900, 0.459700 }, { 0.000100, 0.000500, 0.003400 } }, { "Lowfat Chocolate Milk", { 0.428200, 0.501400, 0.579100 }, { 0.000500, 0.001600, 0.006800 } }, { "Regular Chocolate Milk", { 0.735900, 0.917200, 1.068800 }, { 0.000700, 0.003000, 0.010000 } }, { "Coke", { 0.714300, 1.168800, 1.716900 }, { 0.696600, 1.148000, 1.716900 } }, { "Pepsi", { 0.643300, 0.999000, 1.442000 }, { 0.637500, 0.984900, 1.442000 } }, { "Sprite", { 0.129900, 0.128300, 0.139500 }, { 0.123000, 0.119400, 0.130600 } }, { "Gatorade", { 0.400900, 0.418500, 0.432400 }, { 0.161700, 0.125800, 0.057900 } }, { "Chardonnay", { 0.157700, 0.174800, 0.351200 }, { 0.154700, 0.170100, 0.344300 } }, { "White Zinfandel", { 0.176300, 0.237000, 0.291300 }, { 0.173200, 0.232200, 0.284700 } }, { "Merlot", { 0.763900, 1.642900, 1.919600 }, { 0.758600, 1.642900, 1.919600 } }, { "Budweiser Beer", { 0.148600, 0.321000, 0.736000 }, { 0.144900, 0.314100, 0.728600 } }, { "Coors Light Beer", { 0.029500, 0.066300, 0.152100 }, { 0.026800, 0.060800, 0.152100 } }, { "Clorox", { 0.160000, 0.250000, 0.330000 }, { 0.017500, 0.077700, 0.137200 } }, { "Apple Juice", { 0.121500, 0.210100, 0.440700 }, { 0.101400, 0.185800, 0.408400 } }, { "Cranberry Juice", { 0.270000, 0.630000, 0.830000 }, { 0.257200, 0.614500, 0.810400 } }, { "Grape Juice", { 0.550000, 1.250000, 1.530000 }, { 0.542800, 1.250000, 1.530000 } }, { "Ruby Grapefruit Juice", { 0.251300, 0.351700, 0.430500 }, { 0.089600, 0.191100, 0.263600 } }, { "White Grapefruit Juice", { 0.360900, 0.380000, 0.563200 }, { 0.009600, 0.013100, 0.039500 } }, { "Shampoo", { 0.028800, 0.071000, 0.095200 }, { 0.018400, 0.059600, 0.080500 } }, { "Strawberry Shampoo", { 0.021700, 0.078800, 0.102200 }, { 0.018900, 0.075600, 0.098900 } }, { "Head & Shoulders Shampoo", { 0.367400, 0.452700, 0.521100 }, { 0.088300, 0.163700, 0.212500 } }, { "Lemon Tea", { 0.340000, 0.580000, 0.880000 }, { 0.260200, 0.490200, 0.772700 } }, { "Orange Juice Powder", { 0.337700, 0.557300, 1.012200 }, { 0.144900, 0.344100, 0.786300 } }, { "Pink Lemonade", { 0.240000, 0.370000, 0.450000 }, { 0.116500, 0.236600, 0.319500 } }, { "Cappuccino Powder", { 0.257400, 0.353600, 0.484000 }, { 0.192000, 0.265400, 0.327200 } }, { "Salt Powder", { 0.760000, 0.868500, 0.936300 }, { 0.511500, 0.586300, 0.614700 } }, { "Sugar Powder", { 0.079500, 0.175900, 0.278000 }, { 0.065000, 0.159700, 0.257800 } }, { "Suisse Mocha", { 0.509800, 0.647600, 0.794400 }, { 0.187500, 0.289300, 0.379600 } }, { "Pacific Ocean Surface Water", { 3.364500, 3.315800, 3.242800 }, { 3.184500, 3.132400, 3.014700 } },