From infant formula to caramel chocolate bars to the wonderfully decadent Indian confectionery gulab jamun and chum chum, milk powder is used all over the world.
The lack of moisture in the powder means it can’t spoil easily and has an incredibly long shelf life. It’s also a staple of hikers because it’s non-perishable, easy to prepare and lighter than liquid milk. Most importantly, it makes for a nutritious, on-the-go staple.
The biggest producers of milk powder are Europe, New Zealand, China, the US and Brazil, with three million tonnes exported from Europe alone each year. In this article we’ll let you know how powdered milk is manufactured. To find out how milk powder is made in a factory before it ends up in your kitchen cupboard, read on.
A Short History of Powdered Milk
Powdered milk has a fascinating history. As far back as the thirteenth century, the Mongol armies under the leadership of famed warrior Kublai Khan carried a type of sun-dried skimmed milk but this was more like chunks of chewy, chalk-like cheese.
Powdered milk as we know it today was first developed in the 1800s as a way to preserve milk for long periods of time. It quickly became popular among those who had difficulty obtaining fresh milk, such as sailors and soldiers. Over the next half-century milk powder began to be processed on an industrial scale, and advances in science and technology meant that different manufacturing methods became available.
Making Powdered Milk
There are three main ways to answer the question ‘how is powdered milk made’ or ‘how is dry milk made.’
The most common way of making milk powder is by spray drying. It’s a process in which milk is quickly dried into a powder form. To spray dry milk, the milk is first flash-pasteurised to kill any bacteria. Next, the milk is reduced to around 50% of its original mass by steaming it, separating the vapour from the concentrated powder and then condensing the vapour into a liquid to be removed. The milk is then sprayed into a drying chamber, where it’s exposed to hot air. The liquid milk droplets quickly evaporate, leaving behind a dry powder.
Drum drying can have a number of advantages over other drying methods. It’s faster and is believed to produce a higher-quality product. This method involves passing the milk over a thin film on a heated drum which steams the milk, leaving behind the solids to be extracted and ground into a fine powder. Of the three methods listed here, drum drying is the least used as it has a tendency to caramelise the milk, which can leave the solids with a slightly burnt, bitter taste.
Of the three methods describing the process of how powdered milk is made, freeze drying is the most complex, time-consuming and expensive. Freeze drying involves slowly freezing the milk at -50°C to -80°C. The slower it’s dried, the bigger the ice crystals which makes for a better product. The milk is then subjected to a low heat and low pressures in a partial vacuum, which helps a process called sublimation turning the ice from a solid state to a gas. The gas is then condensed and collected, leaving behind a dry powder that remains rich in the proteins and nutrients found in liquid milk.
The final stage of the process of making milk powder is the packaging. It’s usually sold in metal cans or plastic bags and the packaging process is fully automated in the processing plant. This is the final step in the process of how milk powder is manufactured.