How to Carbonate Drinks at Home, With or Without a Machine

Q: What does volumes of CO2 mean?

Volumes of CO2 is a way to describe how fizzy a drink is. It compares the amount of dissolved gas with the volume of the liquid. One volume means the liquid holds roughly its own volume of CO2 gas at normal atmospheric pressure. Brightly sparkling water and sodas sit at the higher end. Gently sparkling drinks hold less. You do not need to measure this at home. It is simply useful to know that fizz can be dialled up or down.

To carbonate drinks at home, you dissolve carbon dioxide (CO2) into a cold liquid under pressure, then keep it sealed and chilled so the gas stays in solution. The easiest way is a home carbonation machine or a soda siphon charged with CO2. A CO2 tank with a carbonation cap is a more adjustable option. Without a machine, you can let yeast or other live cultures produce the gas through fermentation in a sealed bottle. Whichever method you choose, two things matter most: the liquid should be very cold, and the pressure should stay contained until you serve.

This guide explains how carbonated drinks are made, how to carbonate drinks at home with and without a machine, and how to turn your fizz into drinks that suit your guests and your menu.

How are carbonated drinks made?

Carbonated drinks are made by forcing carbon dioxide gas into a liquid under pressure, which makes the gas dissolve. The container is then sealed before the gas can escape. When you open the bottle, the pressure drops. The dissolved gas starts coming out of solution, and that is what forms the bubbles.

Commercial soda producers chill water or flavoured syrup and mix it with CO2 under pressure. They fill bottles or cans while the pressure is maintained, then seal them straight away. Home methods follow the same principle on a smaller scale.

Why temperature and pressure decide how fizzy a drink gets

Cold liquid holds more dissolved gas than warm liquid, and higher pressure pushes more gas into the liquid. This explains most home carbonation results:

Temperature: Water straight from the fridge, at about 2–5 °C (36–41 °F), absorbs CO2 far better than room-temperature water. Warm liquid foams over and goes flat quickly.
Pressure: More pressure means more dissolved gas, up to the limit your equipment and bottles are designed for.
Time and contact: Shaking or resting the sealed liquid helps the gas spread through it.

What does volumes of CO2 mean?

Volumes of CO2 is a way to describe how fizzy a drink is. It compares the amount of dissolved gas with the volume of the liquid. One volume means the liquid holds roughly its own volume of CO2 gas at normal atmospheric pressure. Brightly sparkling water and sodas sit at the higher end. Gently sparkling drinks hold less. You do not need to measure this at home. It is simply useful to know that fizz can be dialled up or down.

How to carbonate drinks at home with a machine

To carbonate drinks at home with equipment, choose one of three options: a countertop soda maker, a soda siphon or a CO2 tank with a carbonation cap. All three inject carbon dioxide into a sealed, cold liquid. They differ in cost, capacity and how much control they give you.

Countertop home carbonation machines

Countertop soda makers screw a bottle onto a unit that holds a refillable CO2 cylinder. Pressing a button or lever releases gas into the water. Many models are designed to carbonate plain water only. You add flavour afterwards, because syrups and juices can foam violently and soil the machine. Some machines are built to carbonate other drinks, so always check your model's instructions.

Chill water in the machine's own bottle for several hours, ideally overnight.
Fill it to the marked fill line. Do not go over, because the headspace is needed.
Attach the bottle securely to the machine.
Press the carbonation button in short bursts. More presses give stronger fizz.
Release the bottle slowly so the pressure vents gently.
Add flavouring by tilting the bottle and pouring the syrup slowly down the side. Then cap it and turn it gently to mix.

Soda siphons

A soda siphon is a pressurised bottle, often made of metal or reinforced glass. It is charged with small single-use CO2 cartridges and dispenses fizzy water through a valve. Siphons are compact, attractive at the table and good for topping up drinks as you serve.

Fill the siphon with very cold water up to the maximum line.
Screw on the head, insert a CO2 charger and screw on the charger holder until the gas releases.
Shake for a few seconds, then chill the siphon for a while before serving.
Dispense by pressing the lever. Keep the siphon upright.

Important: use CO2 chargers made for soda siphons, not cream chargers. Cream chargers contain nitrous oxide (N2O), which does not give a clean, crisp fizz.

CO2 tank with a carbonation cap

A carbonation cap is a reusable bottle cap with a gas valve. It fits standard plastic (PET) soft-drink bottles and connects to a CO2 tank through a pressure regulator. This setup gives the most control and the lowest cost per litre over time. It also lets you carbonate juices, teas or ready-mixed drinks, not just water.

Fill a clean PET soda bottle with very cold liquid, leaving some headspace at the top.
Squeeze the bottle to push out as much air as possible, then screw on the carbonation cap.
Set the regulator to the pressure recommended by the cap and bottle maker. For sparkling water, home users often work in the region of 30–45 psi (roughly 2–3 bar).
Connect the gas line, let the bottle fill and firm up, then shake it to help the CO2 dissolve.
Disconnect it and rest the bottle in the fridge. Open slowly over a sink.

Use only bottles made for carbonated drinks. Never use glass jars or thin water bottles under a CO2 regulator.

How to carbonate soda and flavoured drinks

The most reliable way to make carbonated soda at home is to carbonate cold plain water first, then mix in a flavoured syrup. Sugar, fruit pulp and other solids give bubbles places to form, so flavoured liquids foam hard when gassed directly. Adding syrup afterwards keeps the fizz lively and your equipment clean.

Simple ratio for homemade soda

Start with about 1 part syrup to 5–6 parts carbonated water. Taste, then adjust, because homemade syrups vary in strength. Stir gently or swirl the bottle rather than shaking it.

Flavour ideas and what they taste like

Ginger and lime: spicy, warming and sharp. It works well with rich or fried foods.
Lemon and thyme or rosemary: bright and herbal, with a grown-up, less sweet profile.
Raspberry and mint: fruity and cooling, and a crowd-pleaser at summer gatherings.
Grapefruit and a pinch of salt: bitter-sweet and refreshing, close to a classic tonic-style finish.
Cold-brewed tea, such as hibiscus or green: naturally lower in sugar, with plenty of colour and aroma.

If you use a carbonation cap, you can carbonate an already-flavoured drink directly. Chill it well and filter out pulp to reduce foaming.

How to carbonate drinks without a machine

To carbonate drinks without a machine, use fermentation. Yeast or live cultures eat sugar and release carbon dioxide inside a sealed bottle, which carbonates the drink naturally. This is how traditional ginger beer, root beer, water kefir and second-fermented kombucha get their sparkle. It takes days rather than seconds, and it needs attention, but it creates complex, tangy flavours that machines cannot.

Fermentation methods for natural fizz

Ginger bug: a starter culture made from grated ginger, sugar and water, fed daily for several days until it bubbles. You add a little to sweetened, flavoured liquid, then bottle it.
Water kefir: small, translucent culture grains ferment sugar water. A second ferment in a sealed bottle with fruit or juice builds the fizz.
Kombucha second fermentation: finished kombucha is bottled with a little fruit or sugar and sealed so the gas builds up.
A small amount of yeast: a tiny pinch of baker's or champagne yeast in a sweetened, flavoured liquid is the old-fashioned way to make homemade root beer or ginger beer.

Steps to carbonate a drink by fermentation

Make a lightly sweetened, flavoured liquid. Cool it to room temperature, because hot liquid kills cultures.
Add your starter, such as ginger bug, kefir grains (strained out before bottling) or a tiny amount of yeast.
Pour it into bottles designed for pressure. Swing-top glass bottles or PET soda bottles both work, and PET lets you feel the pressure building.
Leave the bottles at room temperature, usually for one to a few days. Check them daily.
Once a PET bottle feels firm, move all bottles to the fridge. The cold slows fermentation and helps the gas dissolve.
Open slowly over a sink, ideally after chilling.

Fermentation safety and what to expect

Fermented sodas keep producing gas until they are chilled, so leaving them warm for too long can make bottles burst. Refrigerate promptly once they are fizzy, and keep checking. Fermentation also produces small amounts of alcohol, and the amount varies with sugar, time and temperature. Bear this in mind if you are serving guests who avoid alcohol completely, children or anyone who is pregnant. In those cases, a machine-carbonated soda is the more predictable choice.

Other no-machine shortcuts

Store-bought soda water: buy unflavoured sparkling water or club soda and mix your own syrups. This is the simplest way to make carbonated drinks at home without any equipment.
Baking soda and acid: mixing baking soda with citric acid or lemon juice releases CO2. The fizz is short-lived, though, and leaves a slightly salty or soapy taste, so treat it as a fun experiment rather than a party drink.

Dry ice is sometimes suggested for home carbonation, but it can build dangerous pressure in sealed containers and cause burns. Leave it out of everyday drink making.

Comparing home carbonation methods

The best way to carbonate drinks at home depends on how often you drink sparkling beverages, how much control you want and how much effort you are willing to put in.

Method	Speed	Control over fizz	Can carbonate flavoured drinks?	Best for
Countertop soda maker	Seconds	Moderate (number of presses)	Usually water only; check the model	Daily sparkling water, quick sodas
Soda siphon	Minutes	Fixed per charger	Mostly water	Table service, topping up spritzes
CO2 tank + carbonation cap	Minutes	High (adjustable pressure)	Yes, if chilled and filtered	Enthusiasts, large batches, custom drinks
Fermentation	One to several days	Lower; depends on time and temperature	Yes; flavour develops during fermentation	Ginger beer, kefir sodas, tangy craft flavours
Store-bought soda water	Instant	None	Mix after opening	Occasional use, no equipment

How to keep homemade drinks fizzy when serving

Carbonated drinks stay fizzy longest when they are kept cold, poured gently and served in clean, tall glasses. Every warm surface, rough edge or vigorous stir releases dissolved gas.

Chill everything: the drink, the mixers and ideally the glasses.
Pour down the side: tilt the glass and pour slowly, as you would with sparkling wine.
Add fizz last: build syrup, juice and ice first, then top with sparkling water and stir once, gently.
Use large, clear ice: big cubes melt more slowly and give bubbles fewer places to form than crushed ice.
Reseal quickly: cap bottles between pours, and keep opened bottles in the fridge.

Choosing glassware for sparkling drinks

Highball or Collins glass: tall and narrow. It keeps bubbles rising and suits sodas, spritzes and long drinks over ice.
Flute: shows off a fine stream of bubbles. It is good for alcohol-free sparkling toasts.
Wine or balloon glass: lets aromas open up. It works well for herbal or fruit-forward spritzes with garnishes.

Planning carbonated drinks for a gathering

Homemade carbonation is ideal for get-togethers because one batch of sparkling water can become several different drinks, alcohol-free or not, with no extra shopping. Making your own fizz also lets guests choose how sweet or strong their drink is.

Set up a DIY soda bar

Prepare two or three syrups in advance, such as ginger, citrus-herb and a berry.
Keep sparkling water chilled in a siphon or sealed bottles, or carbonate it fresh as needed.
Set out ice, fresh citrus wedges, mint, cucumber ribbons and a small jug of plain water.
Label each syrup with its flavour and suggested ratio so guests can mix with confidence.
Offer alcohol-free versions first and by default. Anyone who wants an alcoholic drink can add a measured splash of spirit or wine to their own glass.

Food pairings for homemade sodas

Ginger soda: spicy dishes, dumplings, fried chicken and grilled meats. The spice and bubbles cut through richness.
Citrus and herb sodas: seafood, salads, goat's cheese and light summer plates.
Berry sodas: cheese boards, charcuterie and desserts such as shortcake or pavlova.
Bitter grapefruit or tonic-style soda: salty snacks, olives and crisps. It is a natural alcohol-free aperitif.
Unflavoured sparkling water: almost anything. It refreshes the palate between courses, especially with rich or creamy food.

Alcohol-free sparkling ideas

Garden spritz: cucumber, a little elderflower syrup and lime, topped with sparkling water.
Sparkling iced tea: cold-brewed tea lightly sweetened and topped with fizz just before serving.
Shrub soda: a spoonful of fruit-and-vinegar syrup (a shrub) topped with soda water, for a tangy, wine-like edge.

Keeping plenty of appealing alcohol-free fizz on the table helps every guest feel included. It also helps people pace themselves, which makes for a more relaxed gathering.

Home carbonation safety essentials

Safe home carbonation comes down to using equipment as designed and respecting pressure.

Use only bottles rated for carbonated drinks, and replace any that are scratched, cracked or past the manufacturer's recommended lifespan.
Never exceed the fill lines or the maximum pressure stated for your machine, cap or bottle.
Store CO2 cylinders and chargers away from heat and direct sunlight.
Open pressurised or fermented bottles slowly, pointing them away from faces.
Refrigerate fermented drinks as soon as they are carbonated.

With cold liquid, contained pressure and a few good syrups, you can make carbonated drinks at home that match your taste and your table. That might be crisp sparkling water for every day, a tangy fermented ginger beer for the weekend, or a colourful alcohol-free soda bar for your next get-together.