How is protein powder made? Whey powder, the type Colorado State University calls the most popular with American consumers, starts as the liquid left over from cheesemaking. Plants filter out fat, lactose and minerals, dry what is left to a powder, then blend in flavour and sweetener. Plant powders run a shorter path: grind, separate the protein, filter, dry.
This is an evergreen explainer. On 15 October 2026 this desk read the US federal definition of whey protein concentrate, 21 CFR 184.1979c, and the two sections that govern the protein line on a label, 21 CFR 101.9 and 21 CFR 101.36, on eCFR, plus CSU’s Food Source Information page on whey powders.
What happens at each step, and what does it change on the label?
| Step | What happens | What it changes on the label |
|---|---|---|
| Cheesemaking | Milk is curdled and the whey drains off. CSU: sweet whey (pH 5.6 or higher) comes from cheddar, mozzarella and Swiss; acid whey (below 5.1) from cottage cheese and ricotta | The protein itself: CSU puts whey at about 50% beta-lactoglobulin and 20% alpha-lactalbumin |
| Separation | Nonprotein constituents removed by “precipitation, filtration, or dialysis” (184.1979c) | Fat, carbs and lactose per scoop fall; protein share rises |
| More filtering | Concentrate becomes isolate as fat and lactose are stripped (CSU) | “Isolate” on the front; CSU says over 90% protein |
| Hydrolysis, optional | Protein partly broken down; CSU calls hydrolysate “predigested” | “Hydrolysate” or “hydrolyzed” in the ingredients |
| Drying | Liquid is dried to powder; Healthline and Wild Society both describe spray drying | A shelf-stable powder |
| Blending | Flavours, sweeteners and other additives go in | Every added gram dilutes protein per scoop |
What does “whey protein concentrate” legally guarantee?
Less than the marketing suggests. The federal rule defines whey protein concentrate as whey with enough nonprotein constituents removed that the finished dry product contains not less than 25 percent protein. Its other specs, on a dry basis: fat 1 to 10 percent, ash 2 to 15 percent, lactose at most 60 percent, moisture 1 to 6 percent.
Two cautions. Part 184 lists direct food substances affirmed as generally recognized as safe; it defines an ingredient, it is not a quality grade for supplements, and nothing in it is an FDA approval of any tub. And the floor is far below the ranges the ranking pages print: CSU gives concentrate as approximately 30 to 90 percent protein, Wild Society’s page says 60 to 80 percent, and CSU explains the trade label “WPC80” as 80 percent whey protein. None of the three ranking pages read (Healthline, Wild Society, CSU) cites 184.1979c or its 25 percent floor. The ingredient name guarantees the floor and nothing above it.
How do you read protein per scoop on the panel?
Ignore the ingredient name and do the division. Powders sold as conventional foods carry a Nutrition Facts panel under 101.9; powders sold as dietary supplements carry Supplement Facts under 101.36, which says protein must be declared when present above an amount that rounds to zero.
- Grams per serving. 101.9(c)(7) states protein to the nearest gram.
- How it is measured. The same paragraph lets protein be calculated as 6.25 times the nitrogen content. The panel figure is a calculation the rule permits, not a count of intact whey.
- Percent Daily Value. 101.36 says %DV for protein uses the corrected amount, the one adjusted by protein digestibility-corrected amino acid score (PDCAAS).
- Amino-only products. 101.36 bars a protein declaration on products containing only individual amino acids.
Divide grams of protein by the serving weight in grams. That ratio, not the word “concentrate”, is what you are paying for.
Does the process tell you anything about contaminants?
No. Filtration and drying concentrate protein; they are not a test for banned substances. That is a batch claim made by a certifier. Our guides cover what NSF Certified for Sport adds over Contents Certified, how to check an Informed Sport batch number and which certifier tests more substances.
FAQ
How is whey protein made?
Cheese plants curdle milk and drain off the liquid whey. Physical separation, which 21 CFR 184.1979c lists as precipitation, filtration or dialysis, strips out nonprotein constituents until the dry product holds at least 25 percent protein. More filtering removes more fat and lactose to make isolate. The liquid is then dried to powder, flavoured and blended.
How is plant-based protein powder made?
By a shorter route. Healthline’s step list runs harvesting, grinding and separating the protein, filtration, then drying. This desk read no regulation or spec sheet for pea or rice protein this run, so it prints no percentage for them. As with whey, the only number that binds a specific tub is the grams of protein on its own panel.
What is protein powder made from?
Colorado State University lists whey, casein, egg, soy, pea and rice among the sources, and calls whey the most popular with American consumers. Whey is a byproduct of cheesemaking. CSU also notes additives such as creatine, glutamine, sugar and sweeteners, so the ingredient list matters as much as the protein source on the front.
Nothing here is medical advice, and none of it rules on a specific tub. The federal rule sets a floor for an ingredient name, not a grade for your shake. The panel on the tub in your hand is the only protein figure that applies to it, and if you are drug-tested, the certificate matters more than the process.