Pressure, temperature and what goes wrong

Carbonating drinks at home

How carbon dioxide gets into a drink, why cold matters most, why sugar and pulp make it foam, and how to do it without improvising a pressure vessel.

Carbonating your own drinks gives a livelier, finer fizz than topping up with soda, and it lets you carbonate a whole batched cocktail. It is also the one home technique where the main risk is the container rather than the drink, which is why this guide starts with safety and gives no pressure numbers to aim for.

Safety first — read this before anything else on the page

Only use equipment made for carbonating — a soda siphon, a home carbonation machine, or carbonation caps on bottles their maker rates for pressure — and only with the gas cartridges or cylinders the maker specifies.
Never improvise a pressure vessel from a jar, a glass bottle not made for pressure, or a container whose rating you do not know. Glass that fails under pressure throws fragments.
Never exceed the pressure the maker states for your equipment, and never fill above the marked line: headspace is part of how the device is designed to work safely.
Release the pressure fully before opening anything, open slowly pointing away from faces, and stop using any vessel that is dented, cracked or leaking.
Many home carbonation machines are made for water only. Putting juice, syrup or a mixed drink in one that is not designed for it can foam into the mechanism and void its safety design.

How the gas gets in

Carbon dioxide dissolves into a liquid under pressure and comes back out as bubbles when the pressure is released. How much will dissolve depends on two things: the pressure of the gas above the liquid and the temperature of the liquid. More pressure pushes more in; colder liquid holds far more. Of the two, cold is the one you control safely, and it is the one most people neglect.

Carbonation is measured in 'volumes': one volume means the drink holds its own volume of CO₂ gas, measured at ordinary pressure. Beer is commonly around two to three volumes; sparkling wine more. Those figures are for those drinks; the charts that turn them into pressures at each temperature were made for beer and do not carry over to a cocktail with alcohol and sugar in it.

Why things foam over

Bubbles need somewhere to start. Pulp, fibres, undissolved sugar, ice crystals and scratches all give dissolved gas a place to form bubbles, which is why a cloudy or pulpy drink foams out of a carbonator the moment pressure drops. Sugar also makes a drink more viscous, so bubbles hold together as foam instead of breaking.

So the drinks that carbonate well are clear, cold and not too sweet. Water carbonates best of all. Strained, clear mixtures come next; citrus juice with its pulp, fruit purées and anything with egg or dairy are the worst. This is why bars clarify a drink before carbonating it.

Alcohol changes carbonation too, and not in a way a simple chart captures: it alters how much gas dissolves and how bubbles behave. A carbonated cocktail can feel more aggressively fizzy than water carbonated the same way.

Carbonates well: Water; clear, strained, cold mixtures; clarified drinks.
Foams: Anything sugary, pulpy or cloudy; fresh citrus juice; purées.
Do not carbonate: Egg, cream or dairy; anything warm; anything in a device made for water only.

Carbonating water versus carbonating a cocktail

For almost every drink on this site, the right approach is carbonated water added at the moment of serving: very cold soda from a fresh bottle or a siphon, poured gently down the side of a glass full of ice. That keeps the bubbles and keeps the pressure where the equipment was designed to hold it.

Carbonating a whole cocktail makes sense only for a batch that is clear and cold, in equipment made for it. Chill the mixture close to freezing first — a freezer batch is ideal — carbonate in stages, and let the foam settle before releasing pressure slowly.

Why CocktailHQ has no carbonation calculator

A calculator would have to say what pressure to use. The only widely published tables are brewing tables, which assume beer; they do not account for the alcohol and sugar in a cocktail, and no comparable table for mixed drinks is published by a source we can verify. A number on a page also invites someone to reach it with equipment that was never rated for it.

What can be said with confidence is the direction of every variable: colder holds more gas, clearer foams less, less sugar foams less, and the equipment's own rating is the limit. That is the guidance here.

The short version

Cold is the variable to control: colder liquid holds far more CO₂.
Pulp, sugar and cloudiness make a drink foam; clear, cold, dry mixtures carbonate well.
Use only equipment made and rated for carbonating, with the maker's gas, and never fill above the line.
For most drinks, very cold soda added at serving is the right answer.