Hi All!
I work on a project of cup of Instant Coffee and I have big problem with the glass material, I can’t control the material of the drink inside it, when the “drink” mesh is a little smaller the the cup it’s look unreal and when it a little bigger it’s render OK but with very dark material. the SSS help a little but it still too dark. 
I’m using HDRI with GI.
Can somebody help?
The Blender file is here: