How to Steam Milk for Microfoam

Microfoam is milk filled with bubbles so small you cannot see them. It looks glossy, pours like wet paint and feels silky on the tongue. It is what makes a well-made latte or flat white taste sweet and smooth, and it is essential for latte art.

This guide walks through steaming with an espresso machine wand: choosing a pitcher and milk, stretching to add air, rolling to break bubbles down, reaching the right temperature, and keeping the foam glossy until you pour. It also covers plant milks and the most common problems.

Equipment and milk

A stainless steel pitcher with a pointed spout makes control easier. Size it to the drink: a 350 ml (12 oz) pitcher suits one or two small drinks, while a 600 ml (20 oz) pitcher suits larger lattes. Fill it to roughly one-third, just below where the spout begins.

Whole milk is easiest to steam because its fat and protein give stable, rich foam. Reduced-fat milk foams readily but feels lighter. Barista versions of oat, soy and almond milk contain added stabilizers and steam much more reliably than standard cartons.

Stretching: adding air

Purge the steam wand into a cloth to clear water. Place the tip just under the surface of the milk, slightly off center, and open the steam fully. You should hear a gentle, steady paper-tearing sound as air is drawn in. Keep the tip at the surface by lowering the pitcher as the milk expands.

Stretch only until the milk is lukewarm, about 35 to 40°C (95 to 105°F). The amount of stretching sets the foam volume: a little for a flat white, more for a latte, more still for a cappuccino.

Rolling: building texture

Once you have enough volume, raise the pitcher slightly so the tip sinks just below the surface, and angle it to create a whirlpool. The spinning milk folds larger bubbles in and breaks them down into microfoam.

Continue rolling until the pitcher reaches about 55 to 65°C (130 to 150°F). Many people use their palm on the side of the pitcher: when it becomes too hot to keep your hand on for more than a second or two, stop. A thermometer clip helps while learning.

Finishing and pouring

Close the steam valve before lifting the wand out of the milk, so you do not spray milk. Wipe and purge the wand immediately, before milk dries on it.

Tap the pitcher firmly on the counter once or twice to burst large bubbles, then swirl it to keep the foam and milk combined. The surface should look like wet paint. Pour soon, before the foam begins to separate.

• Close the valve before lifting the wand
• Wipe and purge right away
• Tap, swirl, pour within about a minute

Common mistakes

Most problems come from the position of the wand. Too deep and no air goes in; too shallow and large bubbles form, with a loud screeching sound or splattering. Overheating changes the flavor of milk and breaks down the foam.

• Big bubbles: tip too high; lower it slightly and stretch less
• No foam: tip too deep; start closer to the surface
• Screeching: tip at the wrong angle or too deep during rolling
• Foam separates: you waited too long; swirl and pour sooner
• Cooked taste: milk got too hot; stop earlier

Common questions

What temperature should milk be steamed to?

About 55 to 65°C (130 to 150°F). Milk tastes sweetest in this range. Going much hotter can give a cooked flavor and weaker foam.

Can I resteam milk?

It is best not to. Resteamed milk has less stable foam and tastes flat. Steam only what you need, and discard leftovers or use them in cooking.

Why does oat milk foam poorly?

Standard oat milk lacks the proteins and stabilizers that hold foam. Use a barista version, keep it cold, and stretch a little less than with dairy milk.