Whipped Coffee (Dalgona — Korean Origin, Foam Science)

Whipped coffee, known internationally as Dalgona coffee, became a defining food trend of the early COVID-19 lockdowns in 2020. The name references a Korean honeycomb toffee candy called dalgona, which the whipped coffee foam resembles in colour and consistency. The trend was initiated in South Korea by actor Jung Il-woo, who tried the drink at a Macau café in January 2020 and recreated it on a television programme. Within weeks, the #dalgona challenge spread globally, with millions attempting to whip instant coffee into a cloud-like foam. The foam science behind whipped coffee is straightforward but precise. Instant coffee — specifically, the spray-dried kind containing soluble solids — contains surfactants that lower surface tension and allow air to be trapped when agitated. The standard ratio is 2 tablespoons each of instant coffee, sugar, and hot water, whipped together. The sugar is critical: it stabilises the foam by increasing viscosity, and granulated sugar dissolves more readily than caster in the hot water. Without sugar, or with too little, the foam collapses within minutes. The whipping can be done by hand with a small whisk (5–8 minutes of vigorous whisking), with a hand-held electric mixer (2–3 minutes), or with a milk frother (3–4 minutes). The result should be a stiff, glossy, ribbon-stage foam similar in appearance to softly beaten egg whites. It is then spooned over cold or hot milk. Crucially, Dalgona coffee only works reliably with instant coffee — specifically the type produced by spray-drying, which contains the necessary surfactants. Brewed coffee, espresso, and pour-over cannot be whipped by this method. A version using ground espresso powder (not instant) can be attempted but requires additional stabilisers such as a small amount of cream of tartar.

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