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.

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.

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.

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.

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.

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.

Powder is weighed into plastic tubs or pouches and sealed against moisture, which would make it clump.