Kurtis Bosley looks at the science behind carbonation

There’s no denying the influence that carbonated beverages have had on the cocktail world in recent years. Thanks to bars like PS40, This Must Be The Place, and more recently Double Deuce (that bubbly whisky apple is ace) and plenty more championing the use of Co2 in their cocktail program.

Alongside this rise of in-house carbonation in bars, there has also been more pre-packaged mixers for the punters than ever, with Fever Tree, Fentimans, Cascade and PS Soda all releasing a flurry of new flavours over the years, giving rise to the ‘deluxe mixers’ category.

As bartender’s favourite flavour scientist, Dave Arnold notes, ‘Carbon Dioxide Gas (Co2) gives bubbly drinks a distinctive flavour and texture.’ His book Liquid Intelligence [which I’ve spoken about in these pages before] notes the importance of stabilising, filtering and preserving liquids prior to carbonating.

Believe it or not (this one I’d believe), we do have elements in our mouth that can sense Co2, meaning carbonation is actually a taste, similar to salty and sour. The defining aspect of carbonated drinks is a liquid supersaturated with Co2, to the point it is unable to hold the level of Co2 imparted on it, causing it to bubble.


It’s important to note that the two defining factors in cocktail carbonation are temperature and pressure [also how much room you allow the liquid in the bottle to carbonate]. The higher the pressure in the bottle, the more Co2 the drink will contain [or for those who have studied chemistry, this is Henry’s Law]. If there is a mix in the bottle’s environment of air and Co2, there will be less Co2 being dissolved into the liquid and hence less carbonation.

Although Champagne would have us all believe that bubble size in these liquids is the defining note on quality, it is in fact the quantity of Co2 escaping from the drink that determines how rough and biting that drink will be and how the aromas will be punching the air.

I don’t think we’ve reached the ceiling in regard to carbonated beverages but it’s damn exciting to see where it currently sits and the path to which it is going. Remember carbonation is an ingredient similar to sour, sweet or salty. Too much is as bad as too little!

In short

  • Air is the enemy of carbonation
  • Temperature is key to carbonating cocktails, ensure the liquids are around 0’ Celsius prior to carbonating.
  • Foam issues when force carbonating? Make sure to clarify your liquids, control your temperature and have consistency of liquids.
  • Co2 is more soluble in alcohol than in water, the more alcohol a drink contains, the more Co2 you will need to add when carbonating.
  • Experiment with how much Co2 you force carbonate with, play between 32-44PSI, just remember the higher it is, the more prickly the drink will become.
Corretto Dee Why’s High & Ryeball

Batch into PET Bottle – Carbonate to 42PSI
150ml Makers Mark Bourbon
50ml Gospel Rye
50ml Italicus Bergamot Liqueur
75ml lemon myrtle syrup
250ml lychee juice
75ml verjus
5ml lemon distillate
Pinch salt
280ml water