Vodka, Miscibility, and Density for Dummies

pousse-cafe recipe

One of the interns briefly studied what she called "classic bartending"; the mixing of cocktails that Humphrey Bogart might have recognized. One such concoction was a layered drink called a pousse-café, which is a striped drink in a tall glass made by carefully layering liqueurs of different colors. It probably tastes like cherry cola, but at least it looks interesting. That was probably what eHowian Jim Dorsch was thinking about when he attempted to answer, "Does Vodka Settle to the Bottom of a Mixed Drink?" for OurEverydayLife.com

Dorsch, who claims both a BS and an MS, made a valiant attempt to cover the topic... but he blew it. According to Jim,

"With the exception of layered drinks, most mixed drinks should stay mixed in the short time it takes to drink them."

Frankly, that makes no sense: the whole point of a layered drink is that it only stays layered until you disturb the glass, after which all the layers intermingle and turn into a muddy brown liquid. Besides, Jim forgot that alcohol is miscible in water, which means that it is never going to "unmix" unless enough of the liquid evaporates to raise the concentration of alcohol above the critical point.

Instead of talking about the miscibility of ethanol in water-based mixers (which is everything you'd mix vodka with), Dorsch wandered off into a discussion of  specific gravity, ultimately opining that,

"[Vodka] will float to the top of a drink if it comes out of solution."

Well, that's true... except that vodka is never going to come out of solution in a mixed drink... well, perhaps if you are drinking vodka and olive oil.

And since, as Dorsch mentions, vodka's specific gravity ranges from 0.95 to 0.98 and the specific gravity of olive oil is less than 0.92, in that case the vodka would sink to the bottom of the glass. The drink would taste like crap, though.

So much for a Dumbass of the Day whose MS and BS apparently didn't include any chemistry (or a stint working as a bartender).

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