How Is Powdered Milk Made? The Factory Process, Step by Step

Powdered milk is made by taking almost all the water out of fresh milk, in three moves. The milk is first tested and heated. Most of its water is then boiled off in a vacuum evaporator until a thick concentrate remains. Finally the concentrate is sprayed as a fine mist into a tall chamber of hot air, where the last of the water leaves within seconds and dry powder settles out.

That is the answer to how powdered milk is made, but the machines and the milk supply decide whether a plant earns anything. One kilogram of whole milk powder takes roughly 7 to 8.5 kg of milk, so a plant like the one in a Niir Project Consultancy Services (NPCS) report (8 tonnes of skimmed and 2.67 tonnes of whole milk powder a day) needs about 120 tonnes of milk daily, more than a lakh litres.

How is powdered milk made in a factory, step by step?

Seven steps carry milk from tanker to sealed sack. Settings come from a dairy technology chapter in India's e-PG Pathshala programme, except the evaporator boiling range, which is from the Tetra Pak Dairy Processing Handbook.

1. Receive and test. Chilled milk is checked for acidity (below 0.15% as lactic acid), fat and solids, then filtered. Souring milk curdles on heating, so it is rejected here.
2. Standardise the fat. A separator splits cream from skim milk. Skimmed powder goes forward with fat below 0.1%. For whole milk powder, cream is blended back to a fixed level.
3. Heat the milk. 72°C for 15 seconds makes milk safe, but powder plants usually use 88 to 95°C for 15 to 30 seconds, because the heat also decides how well the powder dissolves and keeps.
4. Evaporate under vacuum. Water boils at about 55 to 70°C in the vacuum, so the milk is not scorched. Concentrate for a spray dryer is 40 to 50% solids.
5. Spray dry. The concentrate is atomised into air that enters at up to 215°C and leaves at about 95°C. Operators watch that outlet temperature, because it sets the final moisture.
6. Cool and sift. Powder is cooled to about 30°C and sifted. Instant grades are lightly re-wetted and re-dried into granules that mix into water without floating.
7. Pack. Bulk powder goes into 25 kg sacks with a plastic liner. Retail packs are sealed pouches or tins, often nitrogen-flushed for whole milk powder because its fat goes stale in air. Finished powder typically holds 3% (whole) to 4% (skim) moisture, against the 5% ceiling in the FSSAI standard for milk powders.

Which machines does a milk powder plant need?

Six machine groups make up the line, and the evaporator and the dryer set its capacity.

The evaporator type carries the longest tail of running cost. The Tetra Pak handbook says a mechanical vapour recompression (MVR) evaporator removes 80 to 100 kg of water per kWh and can halve operating cost against a six-effect steam-driven design, so ask suppliers to quote both.

How much milk goes into 1 kg of milk powder?

Milk is mostly water, so the answer depends on its solids. The table uses the legal minimums in the same FSSAI standard (cow milk 3.2% fat and 8.3% solids-not-fat, buffalo milk 5.0% and 9.0%) and the powder moisture above. These are planning figures from our own arithmetic, not measured plant yields.

Buffalo-milk regions need roughly a fifth less milk per kilo of whole milk powder. Richer milk lowers these figures; plant losses raise them. Read the other way, 1 kg of whole milk powder mixes back into about 8 kg of cow-type milk.

Spray drying or roller drying: which suits a new plant?

Take roller drying seriously only if you will sell skimmed powder alone and capital is the binding limit. For whole milk powder, or for any buyer who specifies solubility, plan on spray drying.

What does a milk powder plant cost, and how much milk must you collect?

Two NPCS project reports on milk powder show the scale involved. Their Figures vary with capacity and location, and a lender will want a plant-specific report.

In the first report machinery is about 40% of project cost, and the 56% break-even means the plant has to run past half its capacity before it stops losing money. The second adds pasteurised milk and cream sales around the same dryer, a business our dairy processing plant guide covers.

By the arithmetic above, the first plant takes in about 120 tonnes of milk a day. A milk powder plant is really a milk-collection business with a dryer attached.

Which FSSAI licence does a milk powder plant need?

The licence tier follows how much milk the unit handles. The FSSAI eligibility sheet dated 4 May 2020 sets these tiers for dairy units, which cover milk products such as powder.

A plant at the scale of the first NPCS report falls in the Central tier. Expect state pollution control board consent and a boiler approval as well; the district industries centre has the current list.

What should you settle before pricing a dryer?

1. Count the milk. Measure what you can collect in the lean months, not the flush months, and size the plant to that. If supply is not built yet, start with our dairy farming business plan.
2. Pick one product. Skimmed powder is the simpler line; whole milk powder adds fat standardisation and more careful packing. Talk to likely buyers first, such as a bakery business.
3. Get matched quotes. Ask for MVR and multi-effect evaporator offers with energy use per kg of water removed.
4. Place yourself in an FSSAI tier from your daily milk volume before fixing the site.
5. Check finance. See which government schemes for manufacturers apply to dairy processing in your state; more sector options are in our dairy manufacturing ideas.

NPCS has prepared project reports since 1994, more than 5,000 across 40+ sectors. An NPCS milk powder project report covers the process flow sheet, machinery with suppliers, inputs, layout, manpower and a multi-year financial model with break-even, in the format banks and schemes typically ask for.

Frequently asked questions

Is powdered milk 100% milk?

Yes, in the standard grades. The FSSAI standard defines milk powder as milk with part of its water removed, and whole milk powder must keep at least 26% milk fat. Dairy whitener, instant mixes and infant products are different products that may carry added ingredients, so read the label.

Does air at 200°C burn the milk in a spray dryer?

No. Droplets spend only seconds in the chamber, and the water leaving each one keeps it far cooler than the incoming air. Operators hold the outlet air near 95°C, which fixes final moisture, and the FSSAI standard caps scorched particles to catch overheating.

What is the difference between whole, partly skimmed and skimmed milk powder?

The difference is fat. Under the FSSAI standard, whole milk powder has at least 26% milk fat, partly skimmed more than 1.5% and less than 26%, and skimmed 1.5% or less. All three share the same 5% moisture ceiling.

Can milk powder be made at home?

Only as a kitchen experiment. Home methods dry thin layers of milk in a low oven or dehydrator, giving a coarse powder with uneven moisture and no safety controls. That suits hobby baking, not sale; a sellable powder needs the evaporator, spray dryer and licence above.