The Science Behind Whipped Instant Coffee
How does instant coffee become whipped? Do you need to use sugar? And why can you only make it with instant coffee?
What is whipped coffee?
Dalgona coffee, also known as whipped coffee, is essentially coffee that has been whipped into a fluffy and creamy texture poured on top of iced milk. It was originated in South Korea and it’s based on an old Korean snack made from caramelized sugar resembling honeycomb candy. Similar to the taste of honeycomb toffee, Dalgona Coffee is sweet and velvety, but it still packs the punch of coffee. The recipe uses four ingredients: instant coffee, sugar, water, and milk.
Why is it so viral?
Dalgona Coffee began its online virality on the popular video app TikTok. Perhaps the main reason Dalgona Coffee became so viral was because of its simplicity. Practically anyone could make it. You didn’t need any fancy tools, extensive knowledge about coffee, or any sort of special skill. After all, Dalgona is made with three very common household ingredients to make something fancy.
Additionally, the Dalgona Coffee trend emerged in the midst of the COVID-19 pandemic and quarantine. An easy, fun, and delicious drink you could make at home with your family and friends? It was the perfect recipe (both literally and figuratively). People shared their successes and failures of making the drink online, which piqued a lot of curiosity and sense of community.
What is foam?
The unique feature of Dalgona Coffee is the fact that the coffee foams or in this case “whips.” Not only that, but the coffee can stay whipped and maintain its shape, unlike most foam based coffees that lose their bubbles after a few minutes. The reason Dalgona Coffee can achieve that “whipped” effect comes from the combined properties in instant coffee and sugar.
In its simplest form, foam is air that has become trapped in a solid or liquid in the form of bubbles. Foam forms when a liquid is agitated and a large volume of gas is distributed throughout the liquid. In this case, the act of whipping agitates the coffee to form bubbles. Additionally, in order to be considered “foam” the bubbles need to maintain their form.
Coffee contains properties that form a substance called “surfactants.” Surfactants essentially lower the surface tension between a liquid and gas, the liquid being coffee and the gas being foam. Visually, a surfactant can be described to look like a tadpole. The head of the tadpole likes water (hydrophilic) and the tail does not like water (hydrophobic). Since the tail end does not like water, it will cling on to or “face” towards air and gas.
In this case, when we whip or froth coffee to form bubbles, the tail end of surfactants will face the bubbles. This essentially creates a barrier around each bubble, reducing the surface tension between the coffee and bubbles. The more we whip and froth the coffee, the more bubble barriers we create, which makes foam.
Why instant coffee?
Dalgona Coffee can be made with either instant espresso or instant coffee. The reason you can’t use regular ground coffee is because it requires a weaker coffee to water ratio (when brewed). The recipe for Dalgona requires a 1:1 ratio of instant coffee to hot water. Using this ratio creates a very concentrated and strong coffee. With less water, there’s more surface area from the coffee for the surfactants to create those bubble barriers and trap the air.
While the coffee makes the foam, the sugar creates the whipped effect. The surfactants in coffee are not enough to keep the bubbles from maintaining their shape. If you foam your coffee without sugar, you’ll notice that after a few minutes the bubbles will either rise up from your coffee or merge together, and collapse. Coffee contains small amounts of oil that can enter those surfactant bubble layers and break down those bubbles.
Sugar dissolves easily in water which makes the coffee have a stronger viscosity. This just means the liquid is thicker, similar to the properties of syrup. Additionally, sugar has a crystal-like property that, when in the coffee mixture, creates another protective layer between the bubbles. This prevents the bubbles from merging and collapsing, and more importantly helps the coffee maintain its whipped form. Combining both concentrated instant coffee and sugar allows more bubbles to form than usual because of those created barriers.
How to make whipped coffee
Making Dalgona is essentially combining the ingredients and whipping them together. There have been a few creative ideas to whip up the coffee, but the concept is still the same.
To make whipped coffee you need four ingredients:
- 2 tbsp Waka instant coffee
- 2 tbsp granulated sugar
- 2tsbp hot water
- 1 cup iced or cold milk/milk alternative
To whip the coffee, you can use any of the following tools (ranked by convenience and time):
- Stand mixer
- Hand mixer
- Whisk (manual whip)
- In a bowl, add in 2 tablespoons of instant coffee, 2 tablespoons of sugar, and 2 tablespoons of hot water.
- Mix and whip the ingredients until the coffee is light brown and has a whipped cream texture. Depending on whipping method this will take between 2-10 minutes.
- In a glass, pour 1 cup of cold milk and your whipped coffee on top.
If you find that your coffee won’t “whip,” here are a couple of important notes to keep in mind:
- Keep a 1:1:1 or equal parts ratio of sugar, instant coffee, and water.
- It does take a while for the coffee to solidify, so you might need to keep whipping longer.
- If you’re manually whipping, you need to put in extra work and whip as fast as possible to agitate the coffee (You might want to take turns with your family or friend for this one).
- Make sure the water is hot, otherwise the instant coffee cannot dissolve properly (although if you use Waka Coffee, it will dissolve in cold water as well).