Milk can be heated carefully in a microwave or by stirring it constantly in a pan on top of the stove.  But nothing beats steam heating and nothing beats a fully automatic coffee machine for this operation.

Steamed milk definitely tastes better than milk heated in any other way.  It is sweeter because your tongue reacts instantly to the decreased surface tension. Steaming milk can be painful or one step closer to becoming a culinary genius.  It’s serious chemistry too.  In addition to violently and rapidly heating the liquid, steam alters the physical characteristics of milk proteins in a process called denaturing.  Changes take place on a molecular level in the milk but the results are cosmic.  Steam-denatured milk can become something quite fascinating – something cold milk simply cannot.  Steamed milk can be inflated, built up into a swollen, lofty lattice.  That is, it can be turned into an extraordinarily cool thing – foam.

Your steaming vessel needs only enough room for the milk to double in volume and to keep the hot swirling mixture from sloshing up the sides.  Almost any sturdy, non-plastic vessel will do the job.  Ceramic and glass containers are heavy and unwieldy.  A stainless steal jug is ideal.

A valve on the steam system on our Sprada machines controls the amount of heat transferred to the milk.  You do not want to get the milk too hot because milk proteins don’t foam well, they just break down.  If they get too hot, they break down completely.  The protein strands float to the surface and coagulate into a ghastly mess – curdled protoplasm.

Three step version to frothing process.

It is essential that you thoroughly clean the nozzle after use and ensure that the apertures are totally free from any milk residue.

Ever wonder why soapy water is almost clear but soapsuds are white? Add a little soap to clear or lightly coloured water and when you shake it up, the suds are white.  Simple physics, diffraction and reflection of light.  Light strikes the bubbles, bounces around and is dispersed and reflected in all frequencies or colours equally.

The same thing happens with milk.  The little globs of fat floating in the milk water reflect light evenly in all colours.  So milk appears to be white.  Milk with lower fat content tends to appear bluish white.