Render experiment using finalRender's early subsurface scattering implementation, a method to calculate the distribution of diffuse light inside a volume (in this case the foam cap). As you can see it was still having problems with 3ds max' energy balancing, hence the dark shadow.
Other techniques being showcased here are (blurry) raytracing with "volumetric attenuation" (a physically correct representation of the "Beer's Law"), image-based lighting using HDRI and refraction caustics.