How does it work?
You need three things:
- A siphon composed of a body (the bottle that holds the mixture) and a head (the part that carries the cartridge and lever). It’s easy to use: the bottle is filled with a liquid mixture and then tightly closed by screwing the head. A compressed gas (nitrous oxide – same as you’ll find in store-bought whipped cream canisters) is injected into the bottle via a disposable cartridge, purchased separately. The siphon is shaken to mix the gas with the liquid.
- Gas. Nitrous oxide injected into the siphon creates pressure several times greater than that in the atmosphere. When the lever is pressed, the liquid is quickly propelled out of the bottle. Freed from the confines of the bottle, the gas causes the mixture to expand and swell. This creates foam with thousands of tiny air bubbles.
- A liquid mixture that contains an ingredient to stabilize and trap air bubbles. Therefore, add a bit of protein (gelatin, egg whites), fat (cream) or a binding agent (flour, starch) if it does not contain enough of it naturally. The result: the firmness of the espuma depends on the quantity used. It may be firm like meringue or runny like a sauce.
Espumas can be salty or sweet, hot or cold. They can be served as an appetizer (try putting them in glass jars – very in!), a garnish or dessert. You can make foam using a fruit or vegetable purée, fish stock, foie gras, chocolate sauce, coconut milk, custard… Basically, anything can be made into foam, or almost anything, as long as the mixture has a good consistency. Take into account that espumas or whipped cream made in a siphon are short-lived and will quickly fall… it is a good idea to serve them at the last minute.
For maximum eating enjoyment, highlight the light and fresh texture of Chantilly creams and espumas made in a siphon by combining them with contrasting textures, such as firm and crunchy. Avoid serving alone or you will feel like you’re eating… air!
You will find siphons in specialty cooking stores or you could also make an order online. Several brands and models are available in the following formats: 250 ml, 500 ml or 1 litre. The 500 ml size is perfect for family recipes and requires only two gas cartridges. The 1 litre model requires more cartridges and this increases its cost of use. You should choose a model that makes both hot and cold. Figure on spending between $80 and $140 for a good quality siphon.
Make sure to buy silver nitrous oxide (N2O) cartridges (called cream chargers) and not golden-coloured carbon dioxide (CO2) cartridges (called soda chargers) that are used to carbonate beverages. They are sold separately (between $8 and $12 for 10).
Directions for use
- Before each use, check inside the head to make sure the gasket (rubber ring) is firmly in place and the valve (the hole through which the foam is released) is in a closed position.
- Always strain your mixture through a fine sieve before pouring into the siphon. This is essential to avoid blockages in the head. Respect the siphon’s maximum fill level.
- Use the number of cartridges indicated in the recipe. Generally, one cartridge is sufficient to make whipped cream in a 500 ml siphon. Two cartridges are required to make espumas. It is normal to hear a slight hissing sound when the cartridge is screwed and unscrewed.
- After injecting each cartridge, shake the siphon several times in an upside down position to allow the gas to evenly blend with the mixture.
- At the time of use, shake the siphon in an upside down position in order to once again blend the gas with the mixture. Hold the siphon with the cartridge positioned vertically and gently press on the lever (or on the cartridge, depending on the model).
- Any mixture that remains will keep for two or three days in the fridge.
- Never open the siphon without emptying all the gas first in order to avoid injury and a huge mess in the kitchen! To empty any gas left in the cartridge, press on the lever in an upside down position until there is no pressure remaining.
For Chantilly creams
- Before adding cream, cool the bottle by placing it under cold water or by sticking it in the fridge. Fill with cream, insert the gas cartridge and tightly close to inject the gas. The siphon is now ready to use. Creams do not have to be refrigerated, unlike cold, gelatin-based espumas.
- Avoid shaking the siphon too much after injecting the gas or before using it: the cream can become too firm and will not be able to exit the bottle, or will become too lumpy.
- A siphon produces lighter whipped cream that is a lot less stable than that made with a whisk or electric mixer. This is because it incorporates two times as much air. It is better to serve it at the last minute.
For cold espumas
- Once the siphon is filled, inject the gas and then place the siphon horizontally in the fridge. Leave it for at least six hours to adequately chill. This cooling period thickens the mixture and helps the nitrous oxide dissolve better.
- Vigorously shake the siphon upside down before using.
- If the texture of the mixture coming out of the siphon is too runny, vigorously shake for a few more seconds and try again.