How protein powder is made
Whey protein powder starts as the leftover liquid from cheesemaking, and that liquid is 93% water.
- stations
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- things upstream
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- raw sources
- 5
- steps from the ground
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The short version
Most protein powder is whey protein, recovered from the thin liquid that drains away when milk is curdled into cheese. Membranes first strain out fat and bacteria, then hold back the proteins while water and lactose slip through. The concentrated protein is sprayed into hot air, where fine droplets dry to powder almost at once, before flavoring and packing into tubs.
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Curdle the milk
Rennet or an edible acid goes into heated milk and the milk proteins called caseins clump into curds. The curds become cheese. The liquid that drains off is whey, about 93% water with roughly 0.8% protein.
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Strain out fat and bacteria
Whey is pumped across a microfiltration membrane whose pores block bacteria, leftover casein and fat. The clear liquid that passes through carries the whey proteins.
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Ultrafilter the protein
A tighter membrane now holds back the proteins while water, lactose and minerals pass through. One pass can concentrate whey 10 to 30 times, giving a liquid that is 35 to 80% protein on a dry basis.
10 to 30 times concentration
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Wash with extra water
For isolate, fresh water is added and filtered out again, carrying off more lactose and minerals each time. This diafiltration pushes isolates past 90% protein by dry weight.
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Spray-dry to powder
The concentrate is atomized into a tall chamber of hot air. Each droplet is so small it dries in moments, so the proteins escape the long heating that would denature them, and the powder falls out at the bottom.
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Blend in the flavor
Plain powder is tumbled with cocoa, sweeteners and flavorings, and some brands add digestive enzymes. The batch must be mixed evenly so every scoop delivers the protein on the label.
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Fill the tubs
Powder is weighed into plastic tubs or pouches and sealed against moisture, which would make it clump.
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Worth repeating
- Modern whey protein traces back to a 1969 request from Coca-Cola to New Zealand's Dairy Board for a protein that would dissolve in fizzy drinks.
- Protein in cow's milk is about 20% whey and 80% casein, while human milk is about 60% whey.
- Consumer Reports found that two-thirds of the protein supplements it tested had more lead in one serving than its safe limit.
Back to the ground
Follow every input upstream and protein powder starts as these 5 raw sources.
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Sources
Cite this page: "How protein powder is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/protein-powder