This is a specialised thermos flask with two compartments separated by a double foil membrane. The hot coffee and whiskey go below the membrane, and the cool cream above.

The tricky part is how to remove the membrane when you want to start drinking; I think some sort of draw-string might work, causing the membrane to slide out gently from between the two fluids. However, I don't want the membrane to come out so crumpled or ripped as not to be re-usable.

Anyway, whatever we do with the membrane, users should note that this thing will work better if, before you're ready to drink it, you store it upside down (convection, and all that).
-- pertinax, May 17 2008

intended for this scenario Strip_20Club
[pertinax, May 17 2008]

forget membranes.

two flasks in one with a pouring spout at each end.
-- po, May 17 2008


Don't you like the feeling when your upper lip goes through the cool cream into the hot, sweet alco-coffee?
-- pertinax, May 17 2008


of course, what's that to do with it? you pour the coffee from one end and then the cream from the other obviously into the same cup then you resolve the problem with the hot coffee affecting the cold cream within the flask. see?
-- po, May 17 2008


Ah! I was planning for when you had no cup. See other idea (linked).
-- pertinax, May 17 2008


A thermos flask relies on a vacuum between the two walls.

How will you maintain a vacuum between the two sheets of your double foil membrane?
-- Wrongfellow, May 17 2008


There will probably be an air space, not a vacuum, between those two sheets. However, provided that, as suggested, the thing is stored upside down until ready for use, we won't have to worry too much about convection, but only conduction and radiation, and I'm hoping that the air and foil, respectively, will be sufficient for them. (In the same way, you don't need to maintain a vacuum between your living room and your cellar in order to keep your cellar cool).
-- pertinax, May 17 2008



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