Steaming milk looks like a trick, but it is two small jobs done in order: add a little air, then heat and spin the milk until it is glossy and warm. Get the order and the stopping temperature right and a cheap steam wand gives you café milk. Get them wrong and you get big bubbles or milk that tastes burnt.

Why the temperature matters most

Milk contains lactose, a sugar that tastes only a fraction as sweet as table sugar. Heating changes how it tastes, and the sweetness peaks at about 60°C (140°F). Past that point the flavour turns flat, then scorched. Milk also holds proteins that unravel when heated and then wrap around air bubbles to hold them in place. Above roughly 60–70°C they have unravelled too far to do that job well.

That is why the usual advice is to stop at 60–65°C (140–150°F). Above about 70°C (158–160°F) the milk tastes thin and burnt, and it cannot be fixed or reheated. Always start with cold milk straight from the fridge: it gives you more time to add air before the milk gets hot.

Two moves: stretch, then texture

Stretch means adding air. Hold the tip of the steam wand just below the surface and you hear a soft tearing "tch-tch" sound. This makes the milk grow in volume. A few seconds is plenty: roughly 2–4 seconds for a latte and 4–6 seconds for a cappuccino with a thicker foam. Exact timings vary with how strong your wand is and how much milk is in the jug.

Texture means sinking the tip deeper, so the milk spins in a whirlpool. This folds the bubbles back into the liquid and makes them tiny, so the milk looks glossy like wet paint, not foamy like a bath. Keep spinning while it heats until the jug feels hot to hold, but not painful. A kitchen thermometer clipped to the jug is a good teacher until your hand learns.

Step by step, in 40 seconds

1. Pour cold milk into a jug until it is a little under half full. Whole milk is the easiest to start with.
2. Purge the wand for a second to clear any water, then put the tip just under the surface, slightly off centre.
3. Stretch: let in air for the time you want, listening for the soft tearing sound.
4. Texture: sink the tip deeper so the milk spins. Keep it spinning as it heats.
5. Stop when the jug is too hot to hold for long, at about 60–65°C, then switch the steam off before you lift out the wand.
6. Tap the jug on the counter and swirl it. Pour straight away: milk that sits will separate.

Variations: other milks and no machine

Oat and soy milks can be steamed, but they behave differently from dairy milk, and some brands are made for it, so read the carton. Keep to the same gentle 60–65°C with them. If you have no steam wand, a handheld whisk froths cold milk without heating it, and an electric jug frother heats and froths for you. With the jug you give up some control of the air, but it takes care of the temperature.

The same rules apply to a hot chocolate, a chai latte or a hot milk at bedtime. Warm milk is sweeter than cold milk even without sugar.

What to look for in a frother

If you do not have an espresso machine with a wand, a frother is the easiest way to get warm, foamy milk. Whatever the price, check these things:

• Heating: a jug that heats the milk itself and switches off automatically, so it cannot scorch. If the maker states a temperature, 60–70°C is the range you want.
• Hot and cold settings: useful if you also want cold foam for iced coffee.
• Capacity: check the minimum and maximum fill lines, and that the minimum suits a single cup if you are usually alone.
• Easy cleaning: milk residue is hard to remove, so pick a jug with a non-stick surface and few corners.

The picks below are examples at different budgets, not reviews. Links are affiliate links, which means the site may earn a small commission if you buy.