Chocolate Mousse Espuma
Air made of chocolate
The iSi siphon performs a kind of magic that never quite loses its novelty. You put liquid in one end, charge it with a gas cartridge, and dispense something that resembles clouds from the other. The nitrous oxide forces itself into the liquid under pressure, and when released, it expands into countless tiny bubbles, transforming cream into foam and sauces into air.
This chocolate mousse takes the simplest possible approach: chocolate, cream, and egg whites in equal measure, charged once, and dispensed into whatever vessel strikes your fancy. The temperature at which you serve it determines the texture. Room temperature gives you something ethereal—a chocolate-scented vapor that dissolves on contact with your tongue. Refrigerated, it sets into something closer to traditional mousse, with body enough to hold its shape but still impossibly light.
The technique requires some experimentation. The right moment to charge the siphon—after the chocolate-cream mixture has cooled just enough to incorporate the whites, but before it sets—varies slightly with your ambient temperature and the specifics of your chocolate. A few practice runs will teach you the feel of it. The result is worth the learning curve: a dessert that looks like it required serious pastry training but in fact takes all of ten minutes.
Method
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1
Warm the cream
Heat cream in a small saucepan until it just begins to simmer. Remove from heat immediately.
💡 Do not boil—overheated cream will seize the chocolate.
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2
Melt the chocolate
Pour hot cream over chopped chocolate in a bowl. Let sit for 30 seconds, then stir gently from the center outward until completely smooth and glossy.
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3
Cool slightly
Let the chocolate mixture cool for 10-15 minutes. It should be warm but not hot—about body temperature when you touch it.
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4
Add egg whites
Add egg whites to the cooled chocolate mixture. Whisk until completely incorporated and smooth.
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5
Charge the siphon
Pour mixture through a fine-mesh strainer into a 0.5L siphon. Seal and charge with one N2O cartridge. Shake vigorously for 10 seconds.
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6
Choose your texture
For chocolate air (lightest), dispense at room temperature. For set mousse (firmer), refrigerate siphon for 30 minutes before dispensing.
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7
Dispense and serve
Hold siphon upside-down and dispense into glasses, cups, or directly onto plates. Serve immediately.
Notes & Tips
Temperature matters
- • Experiment to find your preferred serving temperature. The difference between room temperature and refrigerated is dramatic—essentially two different desserts.
Chocolate selection
- • Use the best chocolate you can afford. With only three ingredients, there's nowhere for quality issues to hide.
Storage
- • The charged siphon keeps refrigerated for up to 3 days. Shake well before dispensing after storage.
Variations
- • Add 2 tbsp espresso to the hot cream for mocha
- • Add 1/4 tsp sea salt for salted chocolate
- • Use milk chocolate for a sweeter, more accessible version
Safety
- • Always follow your siphon manufacturer's instructions. Never exceed the recommended number of chargers. Use food-grade N2O chargers only.