How to Steam Milk: Microfoam for Lattes, Cappuccinos and Flat Whites
Good milk makes or breaks a latte. Well-steamed milk is glossy, smooth and sweet, with tiny bubbles you can’t see, called microfoam. Badly steamed milk is either flat and hot, or stiff and bubbly like soap foam. The good news is that steaming follows the same two steps every time: add air, then mix it in.
This lesson covers the equipment, the steps, the right temperature, how much foam each drink needs, and how to fix common problems. Texturing milk is one of the core competencies in TESDA’s Barista NC II qualification, so it is worth practising until it’s automatic.
What you need
- An espresso machine with a steam wand
- A stainless steel milk pitcher (jug), sized for the number of drinks you’re making
- Cold milk, straight from the fridge
- A damp cloth kept only for wiping the steam wand
- A thermometer while you learn (optional)
How to steam milk, step by step
- Fill the pitcher with cold milk to just below the bottom of the spout. The milk needs room to grow. Starting cold gives you more time to build the foam before the milk gets hot.
- Purge the steam wand for a second or two into the drip tray to clear out water.
- Stretch: add air. Put the tip just below the surface of the milk and open the steam fully. You should hear a soft tearing or chirping sound as air is drawn in. Keep the tip near the surface as the milk rises. Stop adding air once the milk is about body temperature.
- Texture: mix it in. Lower the tip a little deeper and tilt the pitcher so the milk spins in a whirlpool. This breaks big bubbles into fine ones and blends the foam through the milk.
- Stop at the right temperature, between about 55 and 65 °C. When the side of the pitcher is too hot to keep your hand on comfortably, you are close. Turn the steam off before you take the wand out of the milk.
- Wipe and purge the wand straight away so milk doesn’t dry on it.
- Polish the milk. Tap the pitcher on the counter to pop any large bubbles, then swirl it until it looks glossy, like wet paint.
- Pour right away, before the foam separates from the milk.
What temperature should steamed milk be?
La Marzocco recommends steaming until the milk reaches 60 to 65 °C, and warns that much hotter milk scalds and loses its sweetness. The Italian Espresso National Institute’s standard for a certified cappuccino is a little cooler: 100 ml of milk chilled to 3 to 5 °C, steamed until it grows to about 125 ml at around 55 °C. Somewhere between 55 and 65 °C suits most drinks. Many people find milk tastes sweetest towards the lower end.
Café tip: steam fresh milk for each order. Re-steaming leftover milk gives thin, flat foam and a cooked taste.
How much foam for each drink?
| Drink | Foam | How long to stretch |
|---|---|---|
| Flat white | A very thin, silky layer | Shortest. Add only a little air |
| Latte | A thin layer, about 1 cm | Short |
| Cappuccino | A thick, airy cap | Longer. The milk should grow by about a quarter, as in the Italian cappuccino standard |
Our guides to latte vs cappuccino and flat white vs latte explain the drinks in more detail. For the difference between steaming and frothing, see steamed vs frothed milk.
Fixing common problems
| Problem | Likely cause | Fix |
|---|---|---|
| Big bubbles, soapy foam | Tip too high, or air added for too long | Keep the tip just under the surface, and stop stretching at body temperature |
| Loud screeching, no foam | Tip too deep | Raise the tip until you hear gentle chirping |
| Flat, thin milk | Not enough air, or the milk was warm to start with | Stretch a little longer, and use milk straight from the fridge |
| Foam and milk separate in the pitcher | Not enough whirlpool, or waited too long to pour | Texture with a stronger spin, and pour straight away |
| Milk tastes burnt | Too hot | Stop at 55 to 65 °C |
Plant-based milks
La Marzocco suggests using barista versions of plant milks, which are made to foam, and keeping them chilled. Oat is generally the easiest non-dairy milk to steam. Almond tends to separate, and soy foams well but can curdle in hot coffee if the temperature isn’t watched. Plant milks usually need less stretching than dairy milk.
Practise, then try latte art
Practise with water and a drop of dish soap to learn the sound and the whirlpool without wasting milk, then switch to milk. Once your foam is glossy every time, latte art comes next. For the coffee side of a milk drink, our espresso dial-in guide helps you pull a shot that holds up in milk. Our Arabica-Robusta Blend and CB’s Finest are made for milk drinks.
More lessons are in the Caffeine Brothers Coffee Academy.
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