Recap
We use steam to heat milk because we get a payload of extra energy from the latent heat of condensation. We can steam milk to temperature in under 20 seconds, whereas it would take minutes to do so on an induction hob (hot plate).
Steaming milk dilutes it by a significant proportion. Refer to the Cowculator Mark II to maintain certain specifications for beverage strength.
The steam wand requires regular maintenance to counteract calcification, maintain hygiene, and reduce odour.
Steam wand design significantly affects milk foaming performance. When the steam wand has smaller holes and a steam boiler is set to a lower pressure, steaming is easier and the level of aeration of your milk is easier to control. This addition control comes at the expense of workflow efficiency, however.
Milk pitchers almost universally lacked alignment and symmetry of the spout and handle — until the Barista Hustle milk pitcher arrived on the scene.
There are five principal milk pitcher grips. Your grip on the milk pitcher should be refined and practiced to give you control and dexterity.
When planning and assessing latte art, plotting north–south and east–west axes can help you internalise a design more quickly.
Glossary
Absolute pressure The pressure in a perfect vacuum is minus 1.14 bar (-14.7 psi).
Axial alignment The arrangement of parts appending a cylinder which are collinear
Bubble coalescence The merging of bubbles, usually brought about by surface active materials spreading across bubble films, causing thinning; drainage as well as Ostwald ripening contribute to the merging of smaller bubbles into larger ones.
Calcification The buildup of mineral deposits which have precipitated from a solvent
Check valve A one-way valve restricting the reversal of a liquid or airflow
Descaling The process of dissolving mineral deposits that involves the application of a solvent — usually a strong acid
Drawing height A position of the milk pitcher which brings the spout within one centimetre of the surface of a beverage.