How Protein Powder Is Made (and How to Spot a Good One)

In this article

• The 5-Minute Version
• How the raw protein powder is made
• What else goes into your protein
• Combining and blending the ingredients
• Testing (and how you know it's clean)
• Key takeaways

You scoop it into a shaker most mornings. But how does a yellow pea, or milk from a cow, actually become that pale powder?

The short version: it's protein pulled out of a food (milk or a plant), then concentrated, dried, and blended with a few other ingredients. When done well, it's also tested for what shouldn't be there.

Between the field (or the vat of milk) and the pouch in your kitchen sits a chain of processes and decisions. Each decision quietly changes the quality and purity of that protein you end up eating.

This is how protein powder is made, in plain English, with diagrams, from start to finish. As we go, we'll flag the key decisions that matter and how they might be affecting you, so that by the end, you know exactly what to look for and what questions to ask!

The 5-Minute Version

It starts with the source, and the process depends on the type.

Whey and casein protein powder both come from milk. Whey is the watery liquid left after milk is made into cheese. It's pasteurized (heated to kill bacteria), filtered by being passed through one or more membranes to concentrate the protein, then spray-dried into powder (sprayed as a fine mist into hot air, which dries very quickly and is collected).

More filtering means less lactose. An isolate is the more-filtered version, so if dairy upsets you, an isolate is usually the better choice. Casein is the curd from milk (or part of the solid that's not "top quality" from cheese manufacturing), and it takes a similar path.

Plant protein starts with the crop (pea, barley, rice) milled into a fine flour. The protein is then separated from the starch and fiber in one of two ways:

• air-sorting (protein and starch particles are different sizes and weights, so an air stream blows them apart), or
• washing it out with water (the protein is dissolved, made to clump and settle, then washed). It's then dried.

Creating the final recipe. Protein doesn't taste good on its own. Whey has a slightly sour, chemical edge. Pea can be thick, grainy and earthy. Rice is a touch chalky, and so on. That's why other ingredients get added.

A master formulator decides the recipe and ingredients. In many companies, that's often a paid contractor rather than a brand employee. The sort of ingredients added include:

• Gums for body and texture (mouthfeel) that also stop clumping. Some gums are gut-friendly, others worth avoiding (details below).
• Thickeners (like Lecithin) to help the powder mix. "Sunflower" on the label is a better sign than "soy", though more because of how it's processed than the ingredient itself (more later).
• Sweeteners. Whey tends to be sweetened more to hide its chemical notes. Lots of options here (and we'll explore the pluses and minuses of each below).
• Flavors to make it taste better. These can be natural or artificial. "Natural" doesn't always mean what you'd hope, and artificial flavors are usually best avoided (we'll explain why shortly). The best brands use the real ingredient: real cocoa for chocolate, real vanilla bean for vanilla.
• Enzymes. Some products include a protease enzyme blend to help your body digest and use the protein more efficiently (the enzyme pre-digests the protein so you absorb more, and it's easier on your stomach).

Everything is then blended together. Note, the type of blender matters more than you'd expect, enough to decide whether a powder will be free of allergens or only might be. Lastly, premium-quality powders are tested, ideally to a real badge (Informed Sport, NSF Certified for Sport).

Remember: "tested" and "clean ingredients" aren't the same thing. A powder can have a "clean" badge and still contain ingredients known to irritate the gut. Understanding the difference is how you take back control (full details below).

And that is how a protein powder is made.

How the raw protein powder is made

Like any recipe, the ingredients will dictate a lot of the final product. A factory can refine a good raw material, but it can't rescue a poor one.

The factors we'll explore: the raw protein source, how it's processed, where the raw ingredients are grown or produced, and the other ingredients added to make the final powder. Each can have a big impact. Let's dive in.

How is whey protein made?

1. Whey is just the watery liquid that pools on top of a yogurt pot (the leftover from making cheese). About 9 lb of whey comes off every 1 lb of cheese, and 200 liters of milk yields only around ~1.3 kg of whey protein.
2. The milk is pasteurized (heated) to kill bacteria. There are actually two types: a lower temperature for longer, or a higher temperature for a shorter time. Neither has a big impact on the resulting protein quality.
3. Then an enzyme called rennet is added, which curdles it: the solid curds go on to become cheese, and the watery liquid left behind is whey.
4. Next, the whey is filtered to raise the protein. Liquid whey is mostly water, with protein, milk sugar (lactose), fat and minerals dissolved in it. Filtering pushes the whey against a membrane (a barrier with tiny holes sized so the bigger protein can't pass) while water and the small stuff (lactose, minerals) slip through. It's essentially one big sieve. Do it more times (rinsing with a little fresh water to flush out extra lactose in between) and what's left is a higher and higher percentage of protein. This is ultrafiltration, and it gives a concentrate (~35% up to ~80% protein; cheaper powders sit at the low end).
5. To push past ~90% to a whey isolate, makers use one of two routes:
   1. Cross-flow microfiltration is simply an even finer sieve, run cold so the protein isn't damaged; or
   2. Ion exchange, which swaps the sieve for electrical charge. Whey protein carries a tiny electrical charge, so when it's run over a charged material (a resin), it grabs the protein and lets everything else wash away. Note: ion exchange posts the highest protein number, but it can strip out some beneficial minor protein fractions.
6. Finally, the resulting mixture is spray-dried. The liquid is atomized through a very fine nozzle into hot air. The droplets dry so fast that the protein doesn't cook. The dried powder falls to the cone-shaped bottom of the chamber, where it's collected as protein powder.
7. Then the powder is shipped as a whey raw ingredient to be turned into a usable protein powder (more below).

Does the drying method matter? Spray-drying is the standard method. Recently, "freeze-dried" has been touted as a method preferred by some premium brands. The issue? It isn't meaningfully better. A 2024 study found spray and freeze drying kept whey's bioactive proteins about the same. Low-temperature drying is gentler but also much pricier, and only very harsh heat or chemistry damages the protein.

Organic vs conventional milk: does it matter for whey? Organic dairy mainly differs in farming terms: no synthetic hormones, no routine antibiotics, organic feed and more pasture (or space in the field) per cow. Organic and grass-fed milk does carry a little more of the better fat (omega-3 and CLA). But whey processing strips most of the fat out (since we're aiming to get the protein). So for the protein itself, organic makes no useful difference. The reasons to choose organic dairy whey are welfare and farming, not a better protein.

How is plant-based protein powder made?

Plant-based protein starts life as… plants (shocking, we know).

The key, which we'll come back to: where the crop is grown and processed has a huge impact on the quality of the raw protein ingredient.

So for plant-based processes:

1. The crop (pea, barley, rice) is cleaned and milled (ground down) into a fine flour.
2. The protein then needs to be separated from the starch and fiber. This is done in one of two ways.

Wet separation (the common method):

1. First, dissolve the protein. The flour is stirred into water, and a little food-grade alkali is added to make the water slightly alkaline. That dissolves the protein but not the starch and fiber (which stay behind as solids and are spun out in a centrifuge or filtered off). You're left with water that has the protein dissolved in it.
2. Next, the protein has to be coaxed out of the water. A food-grade acid is stirred in to bring the liquid down to about pH 4.5 (mildly tart, like tomato juice). At that exact acidity the protein loses the slight charge that kept it dissolved, so the molecules clump together and fall out. That tipping point is called the protein's "isoelectric point."
3. Collect and rinse. The clumped protein is scooped out and washed, and the spent water is drained off. What's left is a wet protein paste, ready to dry (next step). The result is a purer isolate (~80–90% protein). Roughly 5 kg of peas makes 1 kg of isolate.
4. Dry it, the same way whey is dried. The wet protein paste is sprayed as a fine mist through a nozzle into a chamber of hot air. Each droplet is so tiny that its water flashes off in a second or two, so the protein dries into powder without ever getting hot enough to cook.

Dry air classification:

1. Blow the flour apart. The milled flour is dropped into a moving stream of air inside a chamber with a fast-spinning wheel. It works like winnowing, the old trick of tossing threshed grain into the wind so the light chaff blows away while the heavy grain drops straight down.
2. Let weight do the sorting. The protein particles are the tiny, light ones, so the moving air sweeps them up and carries them out one side. The starch granules are bigger and heavier, so the air can't lift them; the spin flings them out to the wall, where they fall away. Tune the air speed and the two split cleanly.
3. Nothing to dry. No water or solvent was ever added, so there's nothing to dry off. You already have a dry powder. It's less pure, though: a concentrate (~50–55% protein). Fewer steps and less energy, but a much lower purity.

The method shifts a little by crop:

• Pea works as above (and most uses wet separation).
• Soy takes the wet route, but before the milling the beans are defatted first (because they're oily). This involves cracking the beans, rolling them into thin flakes, and stripping the oil out (usually with a hexane solvent, sometimes cold-pressed) before the protein is separated.
• Rice protein is stubborn to dissolve, so here enzymes are used to eat away the surrounding starch and free the protein.
• Barley is usually sprouted first: the grains are soaked and left to germinate for a few days (rinsed and drained, like the sprouts you'd eat at home). Once they start to shoot, they're dried and then milled. Sprouting switches on the grain's own enzymes, which pre-digest the starch and protein and strip out anti-nutrients, so the protein is easier to extract and gentler on your stomach.

The raw material's heavy-metal problem

So that's how the raw ingredient of protein powder is created. Something we're often asked is how heavy metals then end up in plant protein.

The answer comes down to sourcing, and primarily location, location, location.

First, heavy metals are lead, cadmium and arsenic. They're not good for your health. You may have seen an alarming set of results last year that most protein powders break the limits in place for these heavy metals. Those limits are California's Prop 65, and they're set about 1,000× below where harm begins.

The issue is these metals compound over time in your body. You do need to look at heavy metals across your entire diet, drinking water and environment (they don't just come from food). We digress… we'll create a more in-depth article to explain more shortly.

The level of heavy metals in your plant-based protein powder comes down to where the crop is grown and where it's processed:

• Cadmium comes from the soil. The plant draws it up and stores it in the seed, so it's fixed by where the crop is grown, and no factory step removes it.
• Lead often pollutes after harvest (as dust or in the air). It settles during drying, transport and processing. That dust carries lead because decades of leaded gasoline and industrial emissions deposited it into soil and air, which is why heavier-industry regions run higher.

This applies to all plant-based ingredients. And if brands aren't careful with sourcing, it can impact everything. In our own testing, two organic hand-picked cocoas (the most expensive and highest quality) grown the same way at different farms differed up to 20–50× in heavy metals.

None of this makes plant protein the villain; a clean plant powder simply sources well and tests for what's there.

We're going to get into a dirty industry secret here… A lot of so-called cleaner, organic-based plant protein powders exist, but they're often higher in heavy metals (per Consumer Reports 2025, i.e. not just us making outrageous claims with no basis; we know you're probably skeptical of the industry, and you should be).

That leads to two questions: why are they higher in heavy metals, and if brands know this, why do they use them?

Why are they higher in heavy metals? Because much of organic plant-based protein powder is sourced from China. And according to China's own studies:

• nearly a fifth of arable land (19.4%) breaches their pollution limits (which are more lenient than the US's), and
• heavy industry keeps airborne lead higher than in the US.

Note: organic makes sense for whole foods. But as you've seen above, protein powder is fairly heavily processed and washed, so little to no pesticide residue ends up in the final product.

If brands know organic plant-based proteins are higher in heavy metals, why do they use them? Because they're cheaper (many consumers view them as higher quality, even though the opposite is likely true). Yes, the premium, "cleaner" plant-based powder is likely using a cheaper raw ingredient and telling you it's better. We know, another example of why this industry can be terrible.

So what can you do to protect yourself? Ask the brand where the crop is grown and where it's processed. Look for their testing; a good brand will publish it.

For RISE311, we pack about 50% more protein per serving than many powders, yet still test well under Prop 65 for the 4 main heavy metals. And we publish our heavy-metal test results on every batch.

(A dedicated follow-up article will go deeper: how metals are measured, the dose-versus-risk picture, and how the big testing reports compare. Please check back.)

What else goes into the protein (i.e. the other ingredients that make up your protein powder)?

So we've got our raw ingredient protein powder. But on its own, that tastes pretty poor. Most protein powders have other ingredients mixed in, to make them more palatable and sometimes better.

So let's discuss what else goes into the raw protein ingredient to make the final product. These will primarily be gums and thickening agents, flavorings and sweeteners. As always, some ingredients are better than others, and we'll give some hints and tips.

Gums

Gums give the drink body and stop the protein clumping together.

Some brands tell you to avoid gums at all costs. Some tell you there's nothing wrong with gums. Both are wrong. So here's your cheat-sheet guide to which gums are good for you and which are best avoided. The great thing: all gums used are listed on a protein powder label, so they're very easy to spot.

The good gum

• Acacia (gum arabic): a prebiotic that feeds the gut bacteria your gut lining depends on. It's a health supplement in its own right (and your body processes it slowly enough that it doesn't produce gas).

The OK gum

• Xanthan: your gut ferments it (it isn't inert), so it can mean gas for some people. Its bad reputation is mostly because it's often paired with cellulose gum (below).

The bad gums

• Cellulose gum (CMC): the strongest evidence against it. A controlled human trial found it raised gut discomfort and lowered microbial diversity. Picture it stripping the gut lining that protects you from harmful bacteria.
• Carrageenan: linked in lab and animal work to irritating the gut lining (punching holes in the seal that keeps food and bacteria where they belong).
• Polysorbate-80: another emulsifier shown (in animal studies) to disturb the gut lining.
• Guar gum: can cause gas, bloating and looser stools at higher doses; tolerance is individual.

Note: these effects are individual and modest for the amounts added to protein powders. The bigger issue is the number of other food products that contain them, and the cumulative impact that can have on your body.

Note: if acacia is so good, why do so few brands use it? You can probably guess by now: it costs about 15× more than cellulose gum (using it is a deliberate, pricey decision).

Lecithin

Lecithin helps the powder wet and mix. It comes in two key types: soy and sunflower.

Soy lecithin is pulled out of soybeans using hexane, a petroleum solvent and a neurotoxin at the doses factory workers face. In fact, the EU is now looking at regulating it, given how widely it's used in food products.

Sunflower lecithin is cold-pressed (like for olive oil) and therefore a much safer choice.

Shock horror: despite the health issues, soy is the more widely used ingredient. Why? Yes, it's down to cost (sorry, I'm sure you're getting bored of that line).

Flavorings

To make the protein taste better, flavors are added. This also helps variety, since most people take a protein powder at least once a day.

Flavors come in three groups: natural flavors, artificial flavors, and the real ingredients.

Artificial flavors are those created in a lab to taste like, or hint at, the flavors of the real ingredients.

Natural flavor is a legal term about sourcing. It means an extract has been taken from a natural ingredient, but not always the ingredient behind the flavor. For example, a natural vanilla flavor can be derived from wood chips. Brands are legally required to use the term "natural flavor", and it's difficult to distinguish between those that derive from real ingredients and those that don't. Which is an issue.

As an example of the difference between a natural flavor and a real one: there are over 200 taste notes within a real Madagascan vanilla bean. The natural variant may pick out only one of those.

To be clear, natural flavors can simply be natural extractions, resins and essential oils from the real ingredient. But it is hard to tell that from the label alone, which means you need to learn more from the manufacturer (or trust the manufacturer is using good sourcing).

And then some brands (like RISE311) add in the real ingredient of the flavor they're using, e.g. organic non-alkalized cocoa or real Madagascan vanilla. This brings a real depth to the flavor, as well as health benefits depending on the exact flavor.

You can probably guess by now why brands might choose artificial flavors over natural, or natural flavors without any of the real ingredient. Yes, you're right. It's cost.

Sweeteners

Sweeteners are added to make the powder taste better, or sometimes to mask flavor notes from a poorer-quality raw ingredient. Sweeteners are where a lot of "clean" marketing claims fall apart, and where some brands add sugar (meaning more calories, usually what you're looking to avoid by taking a protein powder).

The clean ones

• Reb-M stevia: a stevia glycoside present in only trace amounts in the leaf (under 0.1%). This stevia has none of the bitter notes or licorice taste that around 3% of the population can detect. The downside? It costs far more (but it tastes like sugar, with 0 calories).
• Monk fruit: another clean option. It's not as sweet as Reb-M, so you need to include a lot. It also has licorice tasting notes that some people may not love (but it is also 0 calories).

The OK one

• Reb-A stevia: the abundant, cheap glycoside (a few percent of the leaf) that most brands use. When people say they don't like stevia, this is the version they're probably used to and complaining about.

The ones to avoid

• Sucralose and acesulfame-K: carry emerging gut-microbiome concerns.
• Aspartame: classified "possibly carcinogenic to humans" (IARC, 2023, Group 2B, on limited evidence), even as WHO's food-safety panel kept its acceptable daily intake unchanged.
• Sugar alcohols (usually ending in "-ol"): can cause bloating and looser stools at higher doses.

As always, the cleaner sweeteners cost more (Reb-M being the much more expensive, premium option). The ones to avoid are all much cheaper, which is why brands choose them.

Enzymes

Some brands try to give your digestive system a helping hand by including an enzyme blend. Protease is the enzyme your body uses to digest protein. By including it, the powder is much easier on your stomach and also makes the amino acids more available to your body sooner.

How are all the ingredients combined and mixed to create the final protein powder?

Once all the ingredients are chosen, they're mixed together into the final powder. Two things decide how good that blend is: whether the protein is complete, and how evenly it's mixed.

What's a complete protein?

"Complete" means all nine essential amino acids are present at the levels your body actually needs.

Note, some brands get this wrong and state that complete just means it has all the essential amino acids. This is wrong. All protein has all the amino acids. It's the levels that matter.

Whey is a complete protein on its own. A single plant like pea isn't (for example, pea runs short on the amino acids methionine, cysteine and tryptophan). But pairing a legume (like pea) with a grain fills the amino acid gap, so a well-formulated plant blend can be complete too.

There's a score that summarizes this called PDCAAS. It's just a way of summing the levels of all the amino acids and their digestibility, and then comparing against the level your body needs. A score of 1.0 is the best score.

One more thing, brands do need to tell you how much protein is in their pouch. However, telling you the actual amino acid breakdown is allowed (it's a choice). But it's a choice few proteins make (look for the amino acid breakdown on the back of a pouch). This is useful as it allows you to see the level of every amino acid.

This is especially important for the amino acid Leucine, the muscle-building and recovery switch for your body. But we explore more about that in other articles.

Blending

Finally, the last stage of production is blending, where all the ingredients are mixed together. There are two machines most often used:

• A ribbon blender stirs the powder in a trough with a twisting, helical agitator.
• A bin blender tumbles a sealed bin, so the powder never touches the machine.

The most common blender is the ribbon blender. The catch: the same trough and agitator that mix can also trap residue between runs (a real allergen cross-contact risk, and a leading cause of recalls). Most brands use a ribbon blender. Can you guess why?... Yes, cost again.

Bin blenders are sealed for easier cleaning, and bins can be swapped and genuinely sanitized between uses. And yes, RISE311 uses a bin blender.

Last of all comes…

The last step in processing: testing (and how you know it's clean)

(Yes… and we think it's one of the most important.)

Brands are required by law to test for microbes and bacteria. That's a food-safety element.

The very best brands will also test batches for heavy metals and any of the thousands of contaminants that could impact sports performance or other concerns. The great ones publish their results openly.

The tricky part for consumers: you need to be a little careful about what the tests and certificates actually represent. Some examples of important tests:

• NSF/ANSI 455-2 GMP says the facility follows good manufacturing practice (the industry gold standard). This is a process standard, and it matters. But, for example, a brand may use the ribbon blender (with the problems above) and that's still okay under GMP, so long as it's documented, even though the bin blender is demonstrably a better tool.
• Informed Sport/NSF Certified for Sport screens for banned substances (for athletes). While both tests require a heavy-metal analysis, neither requires low levels of heavy metals to pass. In fact, sport-certified powders fail heavy-metal tests all the time.
• Clean Label Project certified tests for contamination of ingredients. It does not mean the ingredients used are high quality. A Clean Label certificate can still sit alongside carrageenan or sucralose (or any other cheaper ingredient with issues).

The key thing to remember: a clean-label badge doesn't mean good-quality ingredients that won't hurt your gut. It means non-contaminated ingredients.

In our view, a clean protein powder should have:

• quality ingredients with no known issues;
• clean processing, with no hidden solvents or extra heavy metals added; and
• testing for heavy metals and sports contamination, with those results published.

And that is how a protein powder is made.

Key takeaways

So that's how a protein powder is made. Protein is extracted through a variety of filtration methods, using alkali or acid solutions to separate it from the starch and fiber. It's dried, then combined with a (hopefully quality) array of ingredients to make it taste great, ideally with some extra health benefits, so it can be enjoyed at home by you.

On that journey, a number of nuances dictate how good the protein really is for you. And these are exactly what let you judge a powder before you put it in your body.

As a quick reminder, the five we think you should look at:

1. Origin & processing: where's the crop grown, and where is the powder processed?
2. Testing: is every batch third-party tested, with a published certificate?
3. Label honesty: does the brand include a full amino-acid panel, or just one big protein number?
4. Formulation: clean gums (acacia, not carrageenan or cellulose gum), solvent-free (sunflower) lecithin, and no artificial sweeteners (and no sugar alcohols ending in "-ol")?
5. Certifications: which badges do they have, and what does each actually cover?

The powder worth trusting is the one that gets all of it right.