Sourdough Discard Banana Bread

Before you start

Banana bread is already a forgiving quick bread, and discard slots into it neatly. The starter adds moisture and a faint fermented tang that reads as depth rather than sourness, and its acidity gives the baking soda a little extra to react with, so the loaf rises with a crackly, domed top.

Because discard brings both flour and water, this formula uses a bit less flour and butter than a standard loaf to keep the balance right. The bananas matter most: use them heavily speckled or fully black, mashed until mostly smooth with a few small lumps. Bake until a skewer comes out with only a few moist crumbs, then let it cool before slicing so the crumb sets.

Ingredients

• 340 g (about 3 large, 1½ cups mashed) very ripe bananas
• 120 g (½ cup) sourdough discard (100% hydration) — unfed
• 100 g (7 tbsp) unsalted butter — melted and slightly cooled
• 150 g (¾ cup packed) light brown sugar
• 2 large eggs — room temperature
• 1 tsp vanilla extract
• 210 g (1¾ cups) all-purpose flour
• 1 tsp baking soda
• ½ tsp fine salt
• ½ tsp ground cinnamon
• 75 g (¾ cup) walnuts or pecans — toasted and chopped; optional

Method

1. Heat the oven to 175°C (350°F) with a rack in the center. Grease the loaf pan and line it with a parchment sling that overhangs the long sides.
2. Mash the bananas in a large bowl. Whisk in the discard, melted butter, brown sugar, eggs and vanilla until well combined.
3. In a separate bowl, whisk the flour, baking soda, salt and cinnamon.
4. Add the dry ingredients to the banana mixture and fold with a spatula just until no dry flour shows. Fold in the nuts. A few small lumps are fine; overmixing makes the loaf tough and tunneled.
5. Scrape the batter into the pan and smooth the top. Bake 55 to 65 minutes, until the loaf is deep brown, the top springs back and a skewer in the center comes out with a few moist crumbs but no wet batter. If the top darkens too fast after 40 minutes, tent loosely with foil.
6. Cool in the pan for 15 minutes, lift it out using the parchment and cool on a rack for at least an hour before slicing.

Tips for success

• Freeze overripe bananas in their peels and thaw them in a bowl; include the liquid they release.
• Older, sharper discard works well here, but very liquid discard should be stirred and measured by weight.
• For a crackly top, sprinkle 1 tablespoon of turbinado sugar over the batter before baking.

Substitutions

Light brown sugar

Granulated sugar gives a paler, slightly drier loaf with less caramel flavor. Dark brown sugar makes it deeper and moister.

Butter

Use 90 g neutral oil. The crumb stays softer for longer but tastes less rich.

All-purpose flour

Replace up to 70 g with whole wheat flour for a heartier loaf; it will be a little denser.

Variations

Chocolate chip

Replace the nuts with 120 g chopped dark chocolate, scattering a few pieces on top.

Banana muffins

Divide into 12 lined muffin cups and bake at 190°C (375°F) for 18 to 22 minutes.

Troubleshooting

Sunken, gummy center

The loaf was underbaked or the bananas were measured by count instead of weight, adding too much liquid. Weigh the mash and bake until the skewer test passes.

Dry, crumbly loaf

Too much flour or overbaking. Spoon and level the flour or weigh it, and start checking at 55 minutes.

Bitter or soapy taste

The baking soda was not evenly mixed or was overmeasured. Whisk it thoroughly into the dry ingredients and use a level teaspoon.

Storage

Wrap the cooled loaf and keep it at room temperature for up to 3 days, or refrigerate for up to a week. Freeze individual slices for up to 3 months.

Safety notes

Do not taste the raw batter; it contains raw eggs and raw flour. Contains wheat, egg, milk and tree nuts if added.