Reese, over at Cocktail Hacker, has a post that I’m going to steal more of than I should, including the picture above, just because it is so cool. He does a small experiment about shaking versus stirring, and gives us the split image picture above, with a shaken Martini on the left and stirred on the right. Reese seems to start his experiment concerned mostly with the aesthetics of the result. I want you to read his post too, so I’ll leave that alone except to say that I actually find that I like my Martinis looking as if you could peer closely and see Kate Winslet and Leo DiCaprio clinging to a piece of flotsam amidst the ice flakes.
I’m more concerned about the bit of science Reese uncovers. His cocktail shaken for 30 seconds came out into the glass at 26 degrees. Stirred a like time, it poured at 46 degrees! When he stirred for 60 seconds, the temp managed to get down to 32. He also noticed, as you can see above, that there was a larger volume in the shaken cocktail, than in the 30 second stir. The 60 second stir almost had the volume of the shaken. Got all that? No? Too bad. I’m not going through that again. Pay attention.
The scientific principal that matters here is that the colder you want your drink, the more diluted it has to be.
Why? Two years ago, Darcy O’Neil wrote a post that pointed out the science behind this. Here is the key fact: Almost all the chill you get from ice in a drink comes from the act of melting itself. A liquid is cooled when you put ice (or even very cold water) in it because the heat energy in the warm ingredients is bled off to raise the temperature of the ice. The cool thing about water is, it takes a fairly small amount of energy to warm up ice or water. But it takes a honking big amount to change ice into water. Here’s a cool graph that shows you it takes almost 80% as much heat to melt ice (which does not raise it’s temp at all) as it does to heat it from 32 degrees to the boiling point!
Why is shaking faster than stirring? Vigorous agitation cracks and slivers the ice, which increases it’s surface area. This makes the heat transfer go faster. It also leaves air bubbles and lots and lots of little needles of ice. These little slivers will go right through the strainer, clouding the drink, along with the bubbles. And these slivers won’t melt very quickly, despite their large surface to mass ratio, because your drink is now below their melting point! Incidentally, if you don’t drink your cocktail quickly (while it is
still laughing at you) these little slivers will melt, and retard the warming speed slightly.
But as the ice melts, it dilutes the drink as well. Some water is needed in most cocktails to make them taste right, but too much and you will have a bland or thin-tasting drink. This is ironic, because the colder the drink, the stronger we can take it, and in fact like it.
And here is where we move from the physics of ice to the sometimes amazing nexus of art and industrial engineering that is modern cocktail bartending.
First, the art. Do you shake or stir? How long? How hard? There aren’t really objective, scientific rules for any of this. You may have a preference so dogmatic and iron-clad that for you it is akin to the Third Law of Thermodynamics, but Pete down the bar there may have an equally strong preference the other way. Chances are, unless you are Gary Regan and want to spend a half-hour instructing an airport bartender how to make a Manhattan, your bartender will decide to shake or stir, and for how long. In this, he or she is an artist. There are many ways to arrive at a great drink with the same ingredients, and many more ways to end up with a crude paint by numbers sketch.
If the bartender is you, in your Basement Bar, you can take the time to be as loving and careful as you like, limited only by your thirst, and that of your guests. But in a crowded commercial establishment, the industrial engineering aspect comes into play. If you ask for a Plymouth Martini, stirred, how likely are you to get Reese’s 32 degree job in any bar, anywhere?
No, not even there.
A bartender who takes sixty seconds to lovingly, gently stir each Martini will be in the weeds so quickly, that his boss will need a DR Trimmer/Mower and/or a price hike to get him out.
So, if you find yourself served a cocktail that looks great, tastes great, is very cold, served quickly, and for an at least somewhat reasonable price, look hard at your bartender. He or she deserves a good reward for their skill and labor. And you need to remember them so you can come back again.