Evergreen88 I’ll try to remember to weigh mine in the morning for comparison. I’m sure you’re aware, but you will always add water when steaming. The reason you can heat milk so quickly is due to the energy released when steam condenses into water, not just the fact hot steam is going through the milk.
Below is my attempt to calculate this for 120g of milk (my normal flat white):
- Physical constants:
- Specific heat capacity of milk: 3.93 kJ / kg.K
- Water enthalpy of condensation: -2257 kJ / kg (at atmospheric pressure)
- temp change required: 5°C to 60°C: 55°C
- Energy required to heat the milk:
- 3.93 kJ / kg.K * 55 K * 0.120 kg = 25.9 kJ
- Amount of water required to deliver this much energy through condensation
- 25.9 kJ / 2257 kJ/kg * 1000 g/kg = 11.5 g
So even with perfectly dry steam, you would expect 11.5 g of water to have been added to 120g of milk due to the physics of how heating with steam works (I.e. 10%].
