In 218 line of the playground: (https://playground.babylonjs.com/#7F6S08#314) there is a material property “alphaMode” that is set for bottle. In the playground it looks like this:
well, that should work out of the box! 
Something is not right. Assigning it to me, and will investigate.
It seems to be working correctly when isolated:
Using this playground - Babylon.js Playground (babylonjs.com)
Do you get the same behavior?
When there is a white ground as a scene mesh, it looks good. It is not good when there is no other meshes in the scene. Example below:
I also tried to change the environment to full white (https://playground.babylonjs.com/#CX9VZA#13) in hope that the glass will be more transparent, and it is when you have ground mesh and above the mesh is black:
It does seem like maximize is simply not supported, though I can’t find any official documentation regarding that so I will continue investigating.
Setting the alpha to a lower value does work as expected -
is that something you will be able to use?
