Why Sourdough Cookies and Scones Aren’t Really “Sourdough”
In recent years, “sourdough” has become a buzzword that’s been stretched far beyond its traditional roots. One trend that’s gained popularity is the use of sourdough starter discard in cookies, scones, and other baked goods. While this practice may add a unique flavor element, calling these products “sourdough” in the traditional, fully fermented sense is misleading.
The short answer is: no, cookies and scones made with discard are not truly sourdough—at least not in the way sourdough bread is. Let’s unpack why that is.
1. Unfermented Flour = Not Sourdough
In most sourdough cookie and scone recipes, a small amount of discard is added to a much larger quantity of fresh flour. The problem? That fresh flour never actually ferments. Fermentation requires time, temperature, and proper hydration—conditions that these recipes don’t typically meet.
This means the core characteristic that defines sourdough—a natural, microbial fermentation process—is absent. Using sourdough discard as an ingredient is not the same as fermenting the entire dough.
2. Low Hydration Stops Fermentation in Its Tracks
Scones and cookies are mixed to a much lower hydration level than bread dough. These stiff, dry doughs have very little free water, and water activity is essential for microbial life. Without sufficient water, wild yeast and lactic acid bacteria cannot effectively grow, reproduce, or metabolize nutrients.
This low water activity is actually what makes cookie and scone doughs so shelf-stable in the fridge. It’s also the very reason fermentation doesn’t happen. If there’s not enough water for microbial activity, there’s no fermentation—plain and simple.
3. Sugar: A Fermentation Antagonist
Sugar, especially in high concentrations (as found in most cookie and scone doughs), poses another challenge. Sugar exerts osmotic stress on microbes, drawing water away from their cells and effectively preserving the dough rather than fermenting it. In other words, it works against fermentation—especially for the delicate balance of wild yeast and bacteria in a sourdough starter.
Even if you removed or reduced the sugar, you'd still be left with the water issue—and fermentation would remain minimal, if not entirely absent.
4. Refrigeration Slows Everything Down
Many “sourdough” cookie and scone recipes call for chilling the dough—either as part of the process or for storage. But when dough is refrigerated, fermentation slows to a crawl. Yeast activity drops off around 7°C (45°F) and becomes nearly dormant at typical fridge temps. Bacteria, which require even more hydration and warmth to thrive, are even less likely to remain active.
Additionally, bacterial fermentation relies on the yeast to first break down complex sugars into simpler forms. If the yeast is inactive, the bacteria have no fuel to work with. So even a long rest in the fridge doesn’t result in meaningful fermentation.
5. Where’s the CO₂?
A clear visual indicator of fermentation is the production of carbon dioxide (CO₂). In sourdough bread, we see bubbles forming in the dough, creating an open crumb structure and visible expansion. This simply doesn’t happen in cookie or scone dough with discard—because fermentation isn’t happening.
If the dough isn’t rising, bubbling, or expanding, it’s a good sign that no real fermentation is occurring.
So Why Use Discard at All?
That doesn’t mean sourdough discard has no place in cookies or scones. It can absolutely lend a pleasant tang, depth, or background acidity—similar to using buttermilk, yogurt, or cultured dairy. But that’s a flavoring function, not a fermentative one.
Calling these bakes “sourdough” because of the discard is like calling a smoothie “fermented” because you added a spoonful of yogurt—it borrows the language without delivering the process.
Conclusion: Call It What It Is
Using sourdough discard in baked goods like cookies and scones can be a smart way to reduce waste and add flavor, but let’s be clear: these products aren’t truly sourdough. They don’t meet the basic criteria of full fermentation, and most of the flour in the final dough remains untouched by microbial activity.
It’s okay to enjoy these recipes for what they are—delicious, creative, and resourceful—but let’s not confuse a clever use of discard with the deeper nutritional and functional benefits of actual sourdough fermentation.
