This High-Protein Sourdough Bread is made with whey protein and packs over 10g of protein per slice, all while tasting just like a classic sourdough loaf. It’s an easy way to add a little extra protein to your breakfast or lunch.
Protein is everywhere in 2026. It’s always been quite popular, but it feels like every product on the shelf is now “high protein.”
So when a friend of mine asked if I’d ever tried making a high-protein sourdough bread, I knew it was a sign. Off to the store I went to grab some unflavored whey protein concentrate. I mixed a double protein shake in a shaker bottle, and swapped it in for the water in my classic sourdough recipe.
The dough was a bit stickier than usual, so I wasn’t sure what to expect. But the loaf came out amazing. Crusty on the outside, soft and tender inside, and the flavor is almost indistinguishable from regular sourdough. Top it with your favorite spreads, and no one would guess it packs two scoops of whey protein.
Each slice delivers about 10.5g of protein—roughly 4g more than a standard sourdough slice.
So if you’re looking for an easy way to sneak extra protein into your day, I think you'll love this high-protein sourdough bread recipe.
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Ingredients & Substitutions
Here are some notes on key ingredients. For a full list of ingredients, check out the recipe card below.
- Active Sourdough Starter- Use a bubbly, recently fed starter for the best rise. You can also use sourdough discard that’s 1–2 days old.
- Protein Powder- I tested this recipe with unflavored whey protein concentrate, but other protein powders should work. Mix it with water first so it incorporates smoothly into the dough.
- Bread Flour- Provides structure, chew, and height. You can substitute all-purpose flour, but the loaf may be slightly denser and not rise as tall.
- Water- Use warm water (80–90°F) to help encourage fermentation.
- Kosher Salt- Enhances flavor and strengthens the dough. I use Diamond Crystal Kosher Salt (2.8 grams per teaspoon). If using Morton’s or table salt, use about half as much by volume or weigh for accuracy.
Tips for Success
- Pick your favorite protein powder. I used unflavored whey protein concentrate, but feel free to use your favorite. Just keep in mind flavored options may slightly change the taste.
- Mix protein shake first. Shake the protein powder and water together until smooth before adding it to the dough.
- Weigh your ingredients. A kitchen scale ensures proper hydration and consistent results every time.
- Start with an active starter. Use a bubbly, recently fed starter for the best rise. You can also use 1–2 day old discard in a pinch, it just may take longer to rise.
- Watch the dough, not the clock. Let it bulk ferment until puffy and roughly doubled. Timing will vary based on your kitchen temperature.
- Let it cool before slicing. Let the loaf rest for at least 2 hours so the crumb can fully set.
How to Make High-Protein Sourdough Bread
Here’s a step-by-step look at how to make high-protein sourdough bread using whey protein concentrate. Full instructions are in the recipe card below.
Step 1: Feed starter. Make sure it’s bubbly and active before mixing the dough.
Step 2: Mix dough. Shake together water and protein powder until smooth, then mix with sourdough starter, flour, and salt to form a sticky dough. Let rest 20 minutes.
Step 3: Stretch and fold. Perform 4 sets of stretch and folds, each spaced 15 minutes apart.
Step 4: Bulk fermentation. Cover and let the dough bulk ferment until doubled and bubbly, about 4–12 hours depending on your kitchen temp.
Step 5: Shape. Stretch the dough into a rectangle. Fold each short end toward the center, then fold the remaining sides like a letter. Flip seam side down and shape into a tight ball.
Step 6: Proof. Place seam side up in a floured proofing basket. Cover and refrigerate overnight (12–16 hours).
Step 7: Bake. Preheat oven to 450°F with a Dutch oven inside. Score the dough, add 2 ice cubes to the pot for steam, and bake 40 minutes covered, then 5–10 minutes uncovered. Let cool at least 2 hours before slicing.
Baker's Timeline
Here’s a sample timeline to help you plan your whey protein sourdough bread.
- 8:00 PM (Night Before): Feed your starter.
- 8:00–8:30 AM: Mix the dough and let it rest for 20 minutes.
- 8:30–9:30 AM: Perform stretch and folds.
- 9:30 AM–5:30 PM (varies): Bulk fermentation (until doubled in size).
- 5:30–6:00 PM: Shape the dough.
- 6:00 PM–6:00 AM (Next Day): Cold proof in the fridge overnight.
- 6:00–6:45 AM: Bake at 450°F.
- 6:45–8:45 AM: Cool completely before slicing.
Note: Rise times can vary depending on the strength of your starter and the temperature of your kitchen. Always use visual cues—like a dough that has doubled and looks airy—rather than relying strictly on the clock.
How to Store
Store high-protein sourdough bread (whole or sliced) in a bread box or airtight container at room temperature for up to 3 days.
For longer storage, slice the loaf and freeze it in a freezer-safe bag for up to 3 months. Thaw slices at room temperature or pop them straight into the toaster or oven to warm through.
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It’s time to turn excess discard into something delicious with my new ebook - Everyday Sourdough!
Inside, you’ll find 27 tried-and-true sourdough discard recipes that will transform your leftover starter into mouthwatering creations your family and friends will love.
No more guilt about wasting your discard - with Everyday Sourdough, you have endless options to quickly make something amazing anytime.
Let's Connect!
Be sure to leave a comment below if you have any questions. You can also connect with me on Instagram, Facebook, Pinterest, or via email at [email protected].
📖 Recipe
High-Protein Sourdough Bread
Equipment
- Protein shaker bottle (optional)
- Straight-sided container (optional)
- Proofing basket or bowl lined with tea towel
- Lame or sharp knife
Ingredients
- 12 ounces (355 grams) warm water 80-90℉
- 2 scoops (65 grams) whey protein concentrate unflavored or flavored
- ½ cup (100 grams) active sourdough starter
- 4 cups (480 grams) bread flour
- 3 ½ teaspoons (10 grams) Diamond Crystal Kosher Salt reduce to 1 ¾ teaspoons if using Morton kosher salt or table salt
- Rice flour for proofing basket
- 2 ice cubes for steam
Instructions
- Feed your sourdough starter 6–12 hours before mixing the dough so it’s bubbly and active. In a cooler kitchen (60–65°F), this may take closer to 12 hours; in a warmer kitchen (around 75°F), about 6 hours.
- In a protein shaker bottle or bowl, vigorously shake together the warm water and protein powder until fully dissolved. Pour the protein shake into a large mixing bowl and whisk in the sourdough starter. Add the bread flour and kosher salt, then mix until a sticky dough forms with no dry flour remaining. Cover and rest 20 minutes.12 ounces (355 grams) warm water, 2 scoops (65 grams) whey protein concentrate, ½ cup (100 grams) active sourdough starter, 4 cups (480 grams) bread flour, 3 ½ teaspoons (10 grams) Diamond Crystal Kosher Salt
- With lightly wet hands, lift one side of the dough, stretch it upward, and fold it over itself. Rotate the bowl 90° and repeat until all four sides have been folded. Gather the dough into a loose ball and place it seam-side down. Cover and rest for 15 minutes. Repeat this process 3 more times (4 total rounds), resting 15 minutes between each set.
- Cover the dough and let it rise until doubled in size and bubbly, about 4–12 hours depending on your room temperature and starter strength. A straight-sided container can help you easily track the rise.
- Turn the dough gently onto a lightly floured surface and stretch it into a large rectangle. Fold one short end toward the center, then fold the other short end over it like you're folding a letter. Fold the remaining two sides toward the center in the same manner. Flip the dough seam side down and shape it into a tight ball by gently pushing and pulling it toward you against the counter.
- Lightly dust a proofing basket (or a bowl lined with a tea towel) with rice flour. Place the dough seam side up in the basket and pinch the seam closed if needed. Cover and refrigerate overnight, or for about 12–16 hours.Rice flour
- Preheat your oven to 450°F with a lidded Dutch oven inside. Once the oven reaches temperature, let the Dutch oven heat for an additional 30 minutes.
- Flip the dough onto parchment paper or a bread sling. Score the top with a lame or sharp knife. Carefully remove the hot Dutch oven, add 2 ice cubes for steam, then lower the dough inside. Cover and bake for 40 minutes. Remove the lid and bake an additional 5–10 minutes, until the crust reaches your desired color.2 ice cubes
- Transfer to a wire rack and let cool for at least 2 hours before slicing.
Notes
- Storage: Store in an airtight container at room temperature for up to 3 days or slice and freeze for up to 3 months.
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