How Shaken and Stirred Martinis Work

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At the annual Science of Cocktails party here in San Francisco, they unlocked one of life’s little mysteries: shaken vs. stirred martinis and which is better.

The event is a fundraiser held at my local (yet famous) science museum, the Exploratorium, where they combine two of my favorite things–science and booze. I really do love this place! This museum is what sparked my interest in science. To this day I thank my cousin Kathryn for taking me here when I was just a tween. If you haven’t been I suggest you visit and do it quickly, the museum is closing from January to April next year to prepare for their move to Pier 15, at SF’s historic waterfront.

Now, I admit that I like my martinis shaken. Why? I do not really know. I have never even had a stirred martini! So, I suspect my decision has more to do with James Bond than anything else.

But I digress, let’s get back to the drinking…uh, I mean science.

Paul Doherty, the Exploratorium’s senior scientist, explains just how one determines the best martini, “We measured temperature, alcohol concentration, and air dissolved in the beverage. The shaken martini came out of the shaker at 20 degrees F after shaking for 15 seconds where the stirred martini only reached a temperature of 32F (temperature of ice).”

But the martinis were warmed to 38 degrees F before we were lucky enough to taste them. And boy were they good! My favorite, pictured above, was swimming with cinnamon and toasted star anise. Yum!

Molecular Mixology Photo via Exploratorium

“We could not measure any difference in alcohol content by measuring the densities of the martinis. Measurement of mass and volume had enough errors that we could not detect a difference in the dilution of the alcohol when the martini encountered the ice. Next time, we’ll use an infrared spectrometer to get a more accurate measurement,” confesses Paul.

So what was the determining factor for shaken vs. stirred? It was air. A shaken martini had almost 10-times more air dissolved in it than a stirred one and was much preferred over a stirred one during the blind taste tests.

The Exploratorium explains how one extracts air from a martini:

Paul placed the martini liquid in a vacuum. He used a syringe to siphon 5 mL of martini mix, sealed the end of the syringe, and then pulled on the plunger to reduce the pressure. The martini mix was then boiled under the reduced pressure. The boiling liquid also outgassed dissolved air. When the pressure was returned to atmospheric level, the alcohol and water vapor immediately returned to the liquid state but an air bubble remained. We compared the sizes of the air bubbles for the shaken versus the stirred martinis and the shaken one were always larger.

If you are looking for some new cocktail recipes, try this concoction:

Fresh Persimmon Pisco Sour

  • 2 oz. ORO Pisco Acholado
  • 3 drops Bitlers
  • 1/2 oz. lime juice
  • 1/2 oz. simple syrup
  • 1/2 egg whites
  • Fresh persimmon

Combine pisco, lime juice, simple syrup, egg while, and ice in a shaker and shake it longer than you meant to.Strain into a rocks glass. Garnish with a lime wedge. Drop the bitters on top.

While many mixed drinks were present at the party, this was the only drink I avoided. And you can see why!

Toilet Beer Photo via Exploratorium

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