A siphon — also called a soda siphon or cream whipper — is one of the most versatile tools in a modern bar. With it you can carbonate cocktails, water and infusions in seconds, or create light airy foams that float on top of a drink.

How it works

A siphon is a pressurised canister, usually made of stainless steel or aluminium, with a valve and a nozzle. You fill it with liquid, screw on a N₂O (nitrous oxide) charger for foams, or a CO₂ charger for carbonation, shake to dissolve the gas, and dispense.

The gas dissolves into the liquid under pressure. When you press the lever, the pressure drops and the gas comes out of solution — carbonating the liquid instantly, or creating a foam.

Carbonating cocktails

Fill the siphon with a finished cocktail — ideally one without egg white, cream or pulpy juice, as these can clog the nozzle. Charge with CO₂, chill for at least 30 minutes, and serve directly into a glass. The result is a cocktail with a fine, persistent fizz that a simple pour over ice cannot achieve.

Rapid infusions

One of the most exciting uses of a siphon is rapid infusion. Place a spirit and your flavouring — herbs, spices, fruit peel — in the canister. Charge with N₂O and let it sit for one to two minutes. The pressure forces the gas into the liquid and opens up the cell structure of the flavouring, dramatically speeding up infusion. Release the pressure slowly, strain and you have a flavoured spirit in two minutes that would take two days in a jar.

Making foams

With N₂O chargers you can turn almost any liquid into a foam. A classic pairing is a citrus foam on top of a Gin Sour, or a coffee foam on an Espresso Martini. The liquid needs some structure — lecithin, egg white, cream or gelatine — to hold the bubbles. Experiment with ratios until you find a foam that holds its shape for a few minutes.

Tips for home use

  • Always chill the liquid before charging — cold liquid holds gas better
  • Strain out any pulp or particles before filling the siphon
  • Release pressure before opening — never unscrew the head while charged
  • Clean the siphon thoroughly after every use to prevent blockages
  • Store charged siphons in the fridge — never in a warm place