Black coffee contains a trace amount of protein, but not enough to count toward your daily intake. A standard 8-ounce cup of brewed coffee has just 0.28 grams of protein. For context, that’s roughly 0.5% of the daily protein most adults need, making coffee nutritionally irrelevant as a protein source.
How Much Protein Is in a Cup of Coffee
An 8-ounce cup of black coffee brewed from grounds contains 0.28 grams of protein. That number stays consistent whether you’re using a drip machine, a pour-over, or a French press, since all methods extract roughly the same tiny fraction of protein from the grounds into the water.
To put that in perspective, a single egg has about 6 grams of protein, more than 20 times what’s in a cup of coffee. Even if you drink four or five cups a day, you’re still looking at barely over 1 gram total. Coffee is essentially a zero-protein beverage.
Where the Protein Comes From
Coffee beans themselves actually contain a meaningful amount of protein, typically between 10% and 13% of the bean’s dry weight. The beans contain several amino acids, with alanine being the most concentrated, followed by asparagine. Robusta beans generally have higher amino acid concentrations than arabica beans.
The reason so little protein ends up in your cup is simple: proteins are large molecules that don’t dissolve easily in water. When you brew coffee, hot water extracts the soluble compounds like caffeine, acids, and flavor molecules, but leaves most of the protein trapped in the spent grounds. You’re essentially drinking the water-soluble fraction of the bean, and protein isn’t a significant part of that fraction.
Roasting Reduces Protein Further
Before the beans even reach your grinder, roasting has already reduced their protein content. As beans roast, the amino acids react with sugars in what’s known as the Maillard reaction, the same chemical process that browns bread and gives seared meat its crust. This reaction consumes amino acids to produce the complex flavor and aroma compounds that make coffee taste like coffee. The longer the roast, the more protein is lost to this process. Research on roasting kinetics found that crude protein in coffee beans steadily decreases as roasting time increases, with losses accelerating depending on the roasting method used.
So darker roasts contain even less protein than lighter roasts, though the practical difference in your cup is negligible since so little protein makes it into the brewed liquid regardless.
What About Coffee With Milk or Additives
If you add milk or cream, the protein content of your drink changes substantially, but that protein is coming from the dairy, not the coffee. An 8-ounce latte made with whole milk contains roughly 8 grams of protein. A splash of milk or cream in black coffee adds 1 to 2 grams. Plant-based milks vary widely: soy milk is comparable to dairy at about 7 grams per cup, while almond and oat milks typically provide 1 to 3 grams.
Collagen peptide powders marketed for stirring into coffee are another popular add-in. Research on collagen hydrolysate dissolved in coffee found that the signature amino acids from collagen are absorbed into the bloodstream at similar rates whether the collagen is mixed into coffee or plain water. Coffee doesn’t appear to interfere with the uptake of added protein supplements, so if you’re stirring collagen or protein powder into your morning cup, you’re still getting the full benefit of those additions.
Why This Matters (and Doesn’t)
If you searched this question because you’re tracking your macros or trying to hit a protein target, the short answer is that you can safely log black coffee as zero grams of protein. It won’t move the needle. The 0.28 grams per cup is a rounding error in the context of a full day of eating, and most nutrition tracking apps already list it as zero.
If you’re looking to boost the protein content of your morning routine, the coffee itself isn’t going to help, but it works perfectly well as a vehicle for protein-rich additions like milk, protein powder, or collagen peptides without reducing their nutritional value.