Assembled · Iced
How to make cold foam for cold brew
Cold foam is milk, and usually a little cream, whipped cold into a thick cap that floats on iced coffee.
- Coffee
- 10 g
- Cup
- 360 ml
- Temp
- 4 °C
- Time
- 1:30
It is not steamed. This page gives one small batch, enough for one glass, and a 90-second sequence. It starts from cold brew you already have, so see the cold brew recipe or the cold brew calculator if you still need to make it. A handheld frother is assumed. It does not cover canned or powdered foams.
The spec
| Part | Amount |
|---|---|
| Cold brew, ready to drink | 150 ml (about 10 g of coffee at 1:15) |
| Ice | 90 g |
| Cold whole milk | 50 ml |
| Cold cream | 20 ml |
| Sweetener, optional | 5 g syrup |
| Foam made | about 120 ml |
| Cup | 450 ml tall glass |
| Total time | 90 seconds |
Cold brew, ice and foam together come to 360 ml in a 450 ml glass, which is four fifths full.
You need
- A handheld electric frother and a tall jug or mug that fits it.
- Cold brew from the fridge.
- Milk and cream straight from the fridge.
- A tall glass and ice.
Ratio 1:15 · Grind: coarse · grind chart
Starting ranges come from your grinder maker’s own guide. Burrs, beans and calibration vary, so treat them as where to begin.
Steps
- 0:00, Ice and 150 ml cold brew in glass.
Put 90 g of ice in the glass and pour in 150 ml of cold brew.
- 0:20, Froth 50 ml milk and 20 ml cream.
Combine 50 ml milk, 20 ml cream and syrup in the jug. Run the frother with its head just under the surface for about 20 seconds, then lower it a little until the liquid thickens to a pourable, soft texture.
- 0:50, Rest so large bubbles pop.
Leave it still for 15 seconds. Big bubbles rise and pop.
- 1:05, Float the foam over a spoon.
Spoon or pour the foam slowly over the back of a spoon so it sits on the coffee.
My notes for this recipe
Why these numbers
Seventy millilitres of liquid for 120 ml of foam. That is a gain of about 1.7 times in volume. The figure is authored, since how much a frother whips depends on the tool, the fat and the cold. It sets how much foam you should see, not a promised outcome.
Why milk plus cream. Milk alone whips thin and fades quickly. A bit of cream makes the foam feel richer and look thicker on the surface. We did not find a controlled study on this, so treat the ratio as an authored starting point: 50 ml milk to 20 ml cream is roughly 5 to 2.
Why everything is cold. Cold milk foams slowly, which gives you time to stop at a soft peak. Warm milk collapses the cap into the coffee. Keep the jug and liquids cold.
Why the base is only 150 ml. A ready-to-drink cold brew over 90 g of ice leaves room above for 120 ml of foam. If your concentrate is stronger, dilute it to about 1:15 first, which is the ratio the cold brew preset uses.
If it looks or tastes wrong
- Foam is runny and sinks. It was not whipped long enough, or the milk was not cold. Froth for five more seconds, and chill the jug.
- Foam is stiff like whipped cream and will not pour. Too long. Next time stop at 20 seconds and rest.
- Big bubbles, no body. The frother head was too near the surface. Lower it just under.
- Foam sinks into the coffee after a minute. Coffee was warm or the ice was melting. Use well-chilled cold brew.
- Too sweet. Drop the syrup, or leave it out. Plain foam is fine.
CupTune has not tested these fixes; they are judgement calls.
Evidence and limits
No cited source supports any number here. The dose of cold brew, foam ratio, milk-to-cream split, froth timing and the 1.7 times volume figure are authored. The 1:15 ratio refers to CupTune's own cold brew preset. The reason cold liquid foams more slowly is a common explanation we have not verified, so use the actual look of the foam over the clock. Fresh cream differs by brand, as does fat content.
Questions
Can I use only milk?
Yes. The foam is lighter and does not hold as long. Use 70 ml of milk and froth the same way.
Can I use oat or soy milk?
They froth differently. CupTune has not tested plant milks, so start with the same timing and adjust by eye.
Can I make the foam ahead?
It loses volume over time. Make it just before you pour.