How powdered milk is made

A tall chamber of air heated to 150 to 250 °C turns a fine spray of milk into powder almost instantly.

stations: 6
things upstream: 1
raw source: 1
step from the ground: 1

The short version

Milk is pasteurized, then boiled down in an evaporator until it is about half milk solids. This thick concentrate is sprayed into a heated chamber, where the water vanishes almost instantly and tiny dry particles of milk solids fall out. An older route scrapes the milk off a heated drum.

Skim off the cream

For nonfat powder the cream is spun out of the milk first. Whole milk powder keeps its fat, and buttermilk and whey can also be dried the same way.

Goes in
Raw milk
Pasteurize the milk

Heat kills the harmful microbes. How hard the milk is heated here changes how well the finished powder dissolves, how it tastes and how densely it packs.
Boil off half the water

An evaporator concentrates the milk until it is about 50 percent milk solids. Removing water this way takes only about 10 to 12 percent of the energy spray drying needs.

about 50% milk solids
Spray into hot air

High-pressure nozzles or a spinning disc throw the concentrate into a heated chamber. Each droplet loses its free water at once and leaves behind a fine particle of dry milk solids.

air at 150 to 250 °C
Finish on a fluid bed

Many plants let the powder leave the chamber slightly damp and finish it on a vibrating bed where air blows up through a plate full of fine holes. Cyclones and bag filters catch the dust from the exhaust.
Pack it airtight

Dry powder keeps far longer than liquid milk and needs no refrigeration, but damp air and warm storage can degrade it, so it goes into sealed bags and cans.

End of the linePowdered milk Next it goes into chocolate, hazelnut spread, white chocolate.

Worth repeating

The first modern process for drying milk was invented by a Russian doctor in 1802.
Drum-dried powder tastes cooked, because the milk sugars caramelize in the heat of the drum.
As of 2021, the largest producers of milk powder were New Zealand, China, Argentina and Brazil.