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MOLECULAR GASTRONOMY: Dry Ice Carbonation

Hi. Pastry Chef Thomas Drahos here again to talk about Molecular Gastronomy at Windows on the Water. And for the uninitiated, Molecular Gastronomy is the art combining food and science to create new and exciting textures and flavors that taste great and are fun to experience. It's what I love doing.

So, for my next subject, lets talk about dry ice. Dry ice is interesting because of the fact that it is composed of frozen co2 gas. Co2 gas is what gives soda, champagne, and Pop Rocks the candy there fizzy sensation. So if Co2 is the basis for carbonation, why use dry ice in cooking rather than Co2 gas, you might ask? I assumed that dry ice would be easier to control because of its solid form. Turns out that I was correct and it worked well for carbonated treats.

The first experiment was simple and just for fun. My first subject? Grapes. What I did was place some whole grapes that were still on the stem in to a plastic container with a lid. Next I crushed the dry ice carefully into a fine powder so as not burn my hands. (Dry ice is 190 degrees below zero! Touching it with bare hands or little insulation can be painful. It is best handled with gloves.) Now, I added the crushed ice into the container of grapes. At first glance this looks like fog over the grapes. This fog is Co2 gas sublimating into the air. (Sublimation happens when a solid evaporates into a gas because of the extremely low freezing point.) I thought if I captured this gas in the container by simply placing an air tight lid on the grapes this might yield a carbonated grape. This worked magically!! I mean it was like eating ''grape soda" right off the vine! Carbonated grapes - the first experiment was a success.

The next idea came about after reading one of my favorite cook books The Fat Duck by Heston Blumenthal. I read that you could make 10 second ice cream with dry ice. It's not hard to imagine how excited I was to get in the kitchen and try this out. The first test was vanilla ice cream. Very basic but also commonly known by foodies. Once again I crushed up the dry ice to a powder but this time I sifted it to get a fine Co2 dust. Then, with a KitchenAid mixer fitted with a paddle attachment, I poured the ice cream base into the mixing bowl. Then I turned the machine on to medium high speed and begin adding the crushed dry ice. And after only about 10 seconds of mixing forms what to me is probably the smoothest ice cream I have ever eaten! Also, to my surprise, some Co2 gas was trapped inside the ice cream causing it to be carbonated! What an unbelievable and pleasant dimension to the ice cream.

Here's a quick video I shot of the above process of making the Dry Ice Cream. It's crude, but fun. Enjoy!