Milk Pasteurization and Milk Sweetness
When steaming milk for espresso, 140ºF (60ºC) is the sweetest temperature to drink. Any further and the lactose and galactose begin to break down and we begin to lose sweetness. Additionally, the further we push the milk in terms of temperature, the harder it is to keep the correct milk consistency and foam levels to what they should be – not to mention latte art. This is why a lot of baristas cringe when a customer asks for a super boiling extra hot cappuccino.
But what about the milk pasteurization process? Often the milk is heated beyond our preferred 140ºF (60ºC), what happens to the milk then?
Milk Pasteurization is heating up milk to kill bacteria such as e.coli, salmonella and Listeria. But at the same time proteins and enzymes are also being effected. There are three methods of pasteurization:
Ultra-Pasteurization – heats the milk to 280ºF (137.8ºC) for only a few seconds.
High-Temp Pasteurization – Milk is heated to 161ºF (71.7ºC) for 31 seconds.
Low-Temp Pasteurization – Milk is only heated to 145ºF (62.8ºC) for about 10 minutes.
We can see that the higher the temperature the milk endures, the more sweetness that will be lost by the final product. Not all sweetness is lost, as we can taste when we have milk. It is still sweet with lactose sugars, but there is potential for a greater level of sweetness when milk is pasteurised at lower temperatures.
For this reason I recommend Low-temp Pasteurization when choosing milk for your coffee.
Another interesting (and controversial) option is Raw Milk, which is not heated at all, although I’m not sure how that steams… yet. If anyone has tried steamed raw milk in a coffee, let me know!
Also any other milk tips welcome 🙂