Sourdough Discard Banana Bread
A moist sourdough discard banana bread using ripe bananas, unfed starter and brown sugar. The discard adds a gentle tang that deepens the banana flavor.
By Maya Ellison · Reviewed by Maya Ellison · Updated August 29, 2026 · 2 min read
Sourdough discard banana bread is the easiest way to spend a jar's worth of unfed starter: ripe bananas, a little brown sugar and that tangy discard fold into a moist, deeply flavored loaf with no yeast and no fuss. The discard's acidity does double duty, tenderizing the crumb and keeping the banana from tasting one-note. Keep the mix gentle and you get a tender slice that's just as good toasted.
Why this recipe works
Banana bread is a quick bread, so it relies on a chemical leavener rather than fermentation. The sourdough discard here is not a substitute for baking soda — it is a flavor ingredient. Its mild acidity brightens the banana and, combined with baking soda, gives a small extra lift and a tender, close crumb.
| Ingredient | Weight |
|---|---|
| Banana | 300 g |
| Sourdough discard | 100 g |
| All-purpose flour | 200 g |
| Brown sugar | 120 g |
The ratio keeps hydration moderate so the loaf bakes through without collapsing.
Mixing and baking
The wet bowl takes the mashed banana, discard, melted butter, eggs and vanilla first. Combine those fully before the dry mix goes in, so the acid from the discard meets the baking soda evenly when you fold.
Fold the flour in by hand and stop at the first sign of no dry streaks. A few lumps are fine and far better than a rubbery loaf. Bake at 350°F and start checking at 50 minutes — the center should read about 200°F and spring back slowly.
Common mistakes
- Tough, chewy crumb: overmixed batter. Fold gently and quit early.
- Sunken middle: underbaked or too much liquid. Use the skewer test and measure bananas by weight.
- Flat flavor: underripe bananas or old soda. Let bananas go spotty black and test the soda.
- Gummy base: sliced while hot. Give it the full hour of cooling.
Before you bake
This is a great home for the jar scrapings you accumulate — the sourdough discard recipes collection has more ways to use them. If you need to build up a jar of discard, the sourdough starter guide covers feeding and storage, and the beginner's guide to sourdough is the place to start.
Ingredients
Weights in grams are the source of truth; cup measures are approximate.
- 300 g ripe banana, mashed (about 3 medium)
- 100 g sourdough discard, unfed, straight from the jar
- 200 g all-purpose flour (about 1 2/3 cups)
- 120 g light brown sugar, packed (about 1/2 cup)
- 100 g eggs (about 2 large), lightly beaten
- 80 g unsalted butter, melted
- 6 g baking soda (about 1 teaspoon)
- 4 g fine sea salt (about 3/4 teaspoon)
- 3 g ground cinnamon (about 1 teaspoon)
- 5 g vanilla extract (about 1 teaspoon)
Method
Heat the oven to 350°F (175°C) and grease a 9 x 5 in loaf pan, lining the base with parchment.
Mash the bananas in a large bowl until mostly smooth, then stir in the sourdough discard, melted butter, eggs and vanilla until combined.
Whisk the flour, brown sugar, baking soda, salt and cinnamon in a separate bowl, then fold the dry mix into the wet just until no streaks remain. Do not overmix or the loaf turns tough.
Scrape the batter into the prepared pan and smooth the top. Bake 50-60 minutes, until a skewer inserted in the center comes out with a few moist crumbs and the top is deep golden.
Cool in the pan 15 minutes, then lift onto a rack. Wait at least 1 hour before slicing so the crumb sets.
Frequently asked questions
Can I use active starter instead of discard?
Yes. Active starter works and gives a slightly milder tang. Because both discard and starter are acidic, the baking soda still has plenty to react with for lift.
Why is my sourdough banana bread dense?
Usually overmixing once the flour goes in, or an expired baking soda. Fold just until combined and check your soda fizzes in vinegar before baking.
Does the discard need to be at room temperature?
Not strictly, but cold discard thickens the batter and can bake a touch unevenly. Let it sit on the counter 20 minutes if it came straight from the fridge.
How should I store it?
Keep it airtight at room temperature for up to 3 days, or freeze sliced for a month. The flavor actually deepens a day after baking.