Soda siphon
A pressure-rated bottle charged with a CO₂ cartridge to make soda water. Its cousin the cream whipper takes N₂O cartridges for foams and rapid infusions; the two are built for different gases and are not interchangeable.
What it's for: Making soda water on demand.
What it changes in the drink
Freshly carbonated water has more fizz than a bottle that has been open for a while, so it lengthens a highball without leaving it flat. That is the main gain. A siphon carbonates water well. It is a poor tool for carbonating a whole cocktail, which needs higher pressure, colder liquid and a vessel designed for it.
Do you need one? Specialist
Small bottles of soda water, opened fresh and very cold, do the same job for most people.
- Good substitute
- Small, single-use bottles or cans of soda water, kept in the fridge so each is opened fresh.
- Poor substitute: a large bottle of soda kept open in the fridge
- It loses carbonation each time it is opened; by the third drink it is flat.
- Typical size
- Commonly 1 litre; charged with one or two small CO₂ cartridges.
Safety
- Use only a purpose-made, pressure-rated vessel with the cartridges its maker names. Never improvise a pressure container from a drinks bottle or a jar.
- Never put juice, syrup or a mixed drink into a siphon made for water unless its maker says it is suitable; sugar and particles foam and block the valve.
- Release pressure before opening, and stop using one that is dented, cracked or leaking.
- Use only a pressure-rated vessel with its own cartridges, never overfill it, and never improvise a pressure container. Release the pressure before opening.
Using it safely
- Fill with very cold water only to the fill line. The headspace is part of the design.
- Screw the head on, then charge it with the cartridge type the maker specifies.
- Shake, then chill for best carbonation; colder water holds more CO₂.
- Release any pressure through the lever before unscrewing the head.
Common mistakes
- Overfilling. Without headspace the gas cannot dissolve properly and the pressure climbs.
- Charging warm water. It holds much less CO₂, and more of it fizzes out on the first pour.
Cleaning and care
Rinse after each use and let it dry open; keep the head's seals clean and replace them as the maker advises.
Technique: Carbonation
What to look for
Buy one sold for the purpose, with its pressure rating and cartridge type stated, and use only the cartridges it names.