Why Does Whiskey and Water Swap Despite Being Miscible?

[In_Development]

Ok, my question arises after seeing this Youtube video (you need to see it to understand what I am talking about):

This may be a part physics, part chemistry question.

Now, I know that ethanol and water are miscible. I also know that in whiskey, you find both ethanol and water. How come, therefore, when he performs the trick in question such a 'swapping' occurs?

Is it because the difference in density somehow overrides the 'diffusion' of the liquids or something?

 

[FredGarvin]

I am not completely familiar with all of the ingredients in whiskey, but there could possibly be some kind of stabilizer or emulsifier that allows the two to be in solution together in whiskey. The trick you saw was a binary system. That makes it very easy to see the differences in specific gravity coming into play.

 

[Bob3141592]

Cool trick. I think diffussion is a slow process, so what little takes place during the time the whiskey and water are in contact probably isn't noticable. Also they're only in contact only at the edges of their flows. Efficient mixing often isn't easy to accomplish. and this setup minimizes the opportunity.

I doubt if the idea of an emulsifier applies. Depending on the proof of the whiskey, there's already a fair bit of water in there.