The good folks who headed up Vessel in Seattle were the same guys who introduced me to carbonated cocktails.
It was a really cool idea. Introduce dissolved gasses into a cocktail, say, a Jack Rose Cocktail, and you’ve got a classy adult soda on your hands. Hopefully with a healthy dose of the bonded stuff.
Beyond the novelty of having a sparkling cocktail without the dilution brought by soda water, the perlage climbing up the flute would bring the aroma to the nose of the drinker. It also opened up or intensified flavor. Take for example, shaken tea. Stirred and chilled, it tastes flat, because it is. Shaken hard, the aeration opens up the flavors and aromas of the tea and even makes it taste sweeter without the addition of simple syrup.
The same concept applies to cocktails. The colder a beverage is, the more sugar must be added for it to taste sweet. With the addition of dissolved gases, the drink may be chilled way down and will take less syrup to sweeten it, allowing for a less viscous mouthfeel to your cocktail.
On to gas mix. Repeat after me: Carbon Dioxide (CO2)=Coarse, Nitrous Oxide (NO)=Fine.
CO2 is great for carbonating viscous liquids. Dissolved, it creates large, coarse bubbles. In terms of ice, think of it as your Kold Draft cubes. It is good for most applications.
NO creates fine, fine bubbles. The reason that isi Whipped Cream canisters use NO gas, is because of these fine bubbles. In heavy cream, the large CO2 bubbles would dissipate quickly, leaving you with a large glob of fat. Tiny NO bubbles whip up a more appetizing glob of fat. It retains in the medium longer because of its size, and the structure holds. That’s why it looks so goddamn pretty. It’s like crushed ice.
So why not just use Nitrous Oxide for all applications?
Because it will explode out of your face. Nitrous oxide dissolves easily in liquids, but it becomes disassociated just as easily. In the glass, a NO-infused cocktail will sit pretty until it comes in contact with a surface with lots of nooks and crannies… like your tongue.
You know the principle behind Diet Coke and Mentos? Same thing, but the Diet Coke is Negroni and the Mentos is your tongue. The bottle? That is your face. Don’t say I didn’t warn you.
I like my face intact and my sinuses devoid of high-proof spirit. Why would I want to use nitrous oxide in my gas mix?
Soda pop is charged with CO2 because of the presence of viscous syrups. Also because it is cheap. Cocktails contain less viscous material, so the addition of NO gas to the CO2-rich siphon gas mix is the difference in mouthfeel between Coke and Champagne.
Is there a simple way of doing this?
Sure. Although, in this method it is most cost-effective to charge them in 32 oz. batches.
1) Fill and cap siphon.
2) Charge with an 8-gram CO2 cartridge. DO NOT SHAKE. Remove the cartridge.
3) Invert the siphon so that an airspace forms at what used to be the base of the siphon and depress the trigger for one second, releasing some CO2.
4) Charge the balance with an 8-gram NO cartridge. Shake hard. Eject the NO cartridge.
That’s it. Four steps to smoother bubbles.