shadows and transparency / refraction

I was just inspired by a combination of couple of reneders of beverages, and the fact that my homebrew needs racking, to make a scene consisting of a demijon full of mead. I got the actually model looking not too bad, could do with work but it’s afirst try. But I ran into trouble getting the shadows to look right. They were ether all dark, or coloured, but not dark with a patch of colour at the center as in the real demijon on my kitch worktop.

With some more experiments I have afeeling this may be due to the light from the lamps not really being refracted. The liquid in the demijon should behave like a lens, but isn’t.

Can this be done in blender?