Science Interviews


Sun, 19th Dec 2010

The Chemistry of Cocktails

Darcy O'Neil, University of Western Ontario

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Chris -   Now, it is our festive Christmas Naked Scientists and I absolutely love cocktails.  We were debating about what our favourite ones are earlier.  I'm a Margarita person, but whatís actually going on, chemically speaking, inside that cocktail shaker?  Well to find out, I got together with the University of Western Ontarioís Chemist and Cocktail Connoisseur, Darcy OíNeil.

Darcy -   Early on, I studied chemistry and then ended up working in a refinery for six years and then I decided to move on to a different city.  I didnít find anything that was really working for me career-wise so I decided to do some bartending, and then I ended up back at the University of Western Ontario and then I decided to take the science and apply it to the drinks that I was making.

Chris -   How did that go down with the customers?

Darcy -   It went down really well.  Usually you think people just come out for a drink, but once they started understanding how the drinks were made and then bringing in some science to it, they really, really took to it.

Chris -   Was it relatively easy to start to dig into the chemistry of cocktails?  Did you actually find that it was pretty easy, from a chemistís point of view, to understand what was going on or is there still just a black bartenderart to cocktail making, and that ďshaken and not stirredĒ is very much on the lips of the consumer, but there isnít much science behind it?

Darcy -   Well, early on, I was probably one of the first dozen people to actually look at the science of cocktails, so there wass a lot of low-hanging fruit to work with.  So, even just talking about ice, why things cool down, how they cool down, talking about how certain things mix.  I mean, that was pretty simply early on.  Now, itís actually getting more difficult because you're always trying to find new material or new and interesting facts that people want to hear.

Chris -   Give us some examples.

Darcy -   Well letís see.  Right now, we are doing essential oils.  There's been this perception that they're artificial flavours, which they're not.  They're just distilled oils, much like ethanol.  You distill off the ethanol, but if you continue distilling a great brandy letís say, you'd end up with cognac oil which comes off at about 110 Celsius.  Itís not artificial, but itís a very, very potent flavour compound that you can make a champagne flavoured non-alcoholic beverage.  So, trying to get people to understand the distillation process, and all that background stuff gets more complicated as we go on.

Chris -   But the interesting thing is, that weíre now in a position where someone like you, who has a lot of chemistry knowledge behind you, can take your knowledge and explain what weíre already doing.  But could we turn the equation around and start saying, ďRight.  Based on what we know about chemistry, we could start doing something very unusual to make a whole new type of drink or cocktail, or a combination, or gustatory experience?

Darcy -   That's actually starting to happen.  Itís following after molecular gastronomy which is the science of food, and what they called it now is molecular mixology, and itís taking science and doing something with the cocktail to create something completely unique.  And one of the most interesting ones or early ones that really got a lot of media attention was caviar.  Itís not really fish eggs, but they look like fish eggs.  So what it was, they would take sodium alginate and calcium chloride, and make a calcium chloride bath, and add a flavour to mix with the alginate, and then drop it into the calcium chloride bath and form these little spheres.  One of the things you could do with these little spheres is to put them on a glass of champagne and they move up and down, like a lava lamp.  People are quite fascinated by it.

Chris -   I remember using that same trick to make immobilised enzymes in the chemistry class at school, but I never thought to put them in champagne.

Darcy -   Yeah and itís funny, thatís where all of the stuff's coming from. A lot of people, itís surprising have high level of education, but enjoy Ė foodís a passion, drinks are a passion, and so, a lot of people bring or cross the information over.

Chris -   Now, one of my favourite characters historically is James Bond for all kinds of reasons, but is there any science behind his shaken and not stirred claims?

Darcy -   Yeah.  Actually, last year, Tales of the Cocktail in New Orleans which is kind of a conference for high-end bartenders and industry people,  looked at the science of shaking because weíve always heard, shaken or stirred, or you know, which one is better and which one produces the mai tai cocktaildifferent drinks.  So they actually did a test.  They took a cocktail shaker and put in a thermocouple, put different amounts of ice, they weighed the ice, and then they'd shake them and see what would happen.  And what they figured out is that for shaking a drink, if you shake it 20 times or for approximately 20 seconds, thatís as cold as itís going to get which is about -7 Celsius.  And then they found with stirring and it takes a lot longer to bring the drink down to that temperature, so probably twice as much time, 40 seconds to get it to that plateau because it actually doesnít really go any colder than -7.

Chris -   There was a company that were claiming that their ice was the best ice for cocktail making, wasnít there?

Darcy -   Yeah.

Chris -   So that basically blows them out of the water.

Darcy -   Well it does.  I mean, you know, there is still good ice and bad ice.  You know obviously, ice picks up a lot of flavours, so using clean fresh ice is always the best idea.  There is no such thing as the perfect ice for a cocktail.  Any ice will do.

Chris -   What about if you used dry ice?  I don't mean that in a funny way, but that would presumably lower the temperature much further.

Darcy -   Definitely and what happens is that it also carbonates the drink.  You'll taste the acidity in it.  So, for a lot of people who do a Halloween type drinks, they like to put the dry ice in it and they get froth and stuff.  And if you've ever tasted it afterwards, it tastes much different.

Chris -   You've tried that, have you?

Darcy -   Yeah, working in a lab, I mean, thereís always something I can try, so bring home dry ice and give it a shot.

Chris -   One of the other things that I heard one person saying with the shaken not stirred business is that when you make a cocktail, some of the things mix quite well with stirring, but there are other heavier things that don't, and actually, shaking the cocktail up does make a very big difference to the way in which the combinations of chemicals mix around, and therefore, the flavour sensation they impart to your tongue and your mouth will differ between shaking and stirring.

Darcy -   Well the funny thing is, one of the studies weíve done at the university I work at, was about bruising gin.  So, what they found was that it really doesnít change that much, but I think the oxidation potential goes up or something like that.  It was a very slight difference, but never let facts get in the way of a good story because thatís part of what drinking is.  You know, you go to a bar and you want to talk about things.  If you're a little bit too matter of fact, it becomes no fun to talk about it.

Chris -   I could not conclude an interview with an expert on the chemistry of cocktails, and I suppose mixology, without asking you, what is your favourite tipple?

Darcy -   Iíd have to say the Manhattan.  If you go to a bar, usually they'll get it right.  Itís not a drink that you mess up too much.  Usually, itís about 2 ounces of whisky Ė not Scotch whisky, but American or Canadian whisky is the general preference.  Half an ounce or two ounce of sweet vermouth and a dash of bitter, Angostura bitters works amazingly well, and just basically stirred as opposed to shaken, and then garnished with a maraschino cherry.

Chris -   And served...

Darcy -   In a cocktail glass, similar to Martini glass, actually we have a Manhattan glass which is a little bit shorter.

Chris -   You got to have the right kit.  Itís very important that a chemist has got the right glassware, isnít it?

Darcy -   Absolutely.  Glassware is something I've got a little bit too much of and itís kind of a collection, and this drink has to have the right glass.

Chris -   So none of those funky plastic tumblers like Dr. Katís fond of when she goes out drinking.  Just joking, Kat.  That was Cocktail Chemist Darcy OíNeil talking to me from the University of Western Ontario, about his work as a molecular mixologist. 


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