Zero Waste Sourdough Discard Banana Quick Bread

a loaf of sourdough discard banana bread cooling in a glass pan on a silver rack placed on a white and gray marble background
Jump to Recipe

This sourdough discard banana bread post came to be after a surplus of apricots forced me to play jar Jenga in my freezer, trying to make space for my bounty. I found mashed overly ripe bananas that I had squirreled away months earlier upon the realization that they would have become compost had I not dealt with them. But I didn’t have time to bake at that moment. Into the freezer they went. (Go here for freezing food in jars.)

Mashed bananas, like so many foods, freeze very well, which prevents food from going to landfill where it emits methane gas, a greenhouse gas much more potent than carbon dioxide. Simply peel the bananas and mash them with a fork until, well, mashed. (I like to use a flat surface to mash them on, such as a plate.) In addition to preserving the food, the freezer also buys you time—you can bake from a few days to several months later. To thaw, move the frozen bananas to the refrigerator the night before you need them.

a mason jar filled with mashed overly ripe bananas and surrounded by other banana bread ingredients
A jar of previously frozen, mashed, overly ripe bananas, thawed

Like baking with still-edible bananas on their way out, baking with sourdough discard also prevents food from going to waste. Every time you feed your starter, you remove most of it from the jar—this is the discard. Instead of actually discarding the discard in the trash, you can bake all kinds of recipes with it:

And now, sourdough discard banana quick bread can take its rightful place on this list! Keep food out of landfill by baking—and eating—yummy quick bread!

You can do one more thing to help prevent food from going to waste—sign this petition asking CVS to stop dumping edible food and other items.

a loaf of sourdough discard banana bread cooling in a glass pan on a silver rack placed on a white and gray marble background
side view of a loaf of sourdough discard banana bread cooling on a wire rack
Interior of sourdough discard banana bread that has been sliced. A slice lies in front of the loaf in a wooden cutting board.
a loaf of sourdough discard banana bread cooling in a glass pan on a silver rack placed on a white and gray marble background
Print Recipe
4.41 from 5 votes

Sourdough Discard Banana Nut Bread


  • ½ cup chopped walnuts or pecans
  • 1 cup all-purpose flour
  • ½ cup whole wheat flour
  • ½ teaspoon salt
  • teaspoons ground cinnamon
  • ½ teaspoon baking soda
  • ¼ teaspoon baking powder
  • 1 large pastured egg
  • ¾ cup lightly packed brown sugar see Note
  • cup mashed overly ripe bananas about 3 medium-small bananas
  • ½ cup unfed sourdough discard stir down to remove bubbles before measuring
  • cup olive oil, plus more to grease the pan
  • 1 teaspoon vanilla extract


  • Preheat the oven to 350°F. Generously grease a 9- by 5-inch loaf pan with a bit of olive oil.
  • As the oven heats, toast the nuts until they are fragrant but not dark, 5 to 10 minutes. Check them after 5 minutes. If they aren't ready, stir them and recheck every minute or two.
  • In a small bowl, whisk together the flours, salt, cinnamon, baking soda and baking powder.
  • In a large bowl, beat the egg until light. Add the sugar, mixing well. Stir in the mashed banana, sourdough discard, olive oil and vanilla.
  • Add the dry ingredients to the banana mixture and stir just until combined. Fold in the nuts.
  • Scrape the batter into the prepared pan and bake for 50 to 60 minutes, until a thin clean sharp knife inserted into the center comes out clean. Cool the loaf in the pan for 10 minutes before inverting onto a rack to cool completely. If necessary, run a knife along the edges of the pan to release the banana bread.


This banana bread is only slightly sweet. If you ordinarily reduce the amount of sugar in quick bread recipes, you may not want to reduce the sugar in this recipe by very much.

My cookbook has been shortlisted for a Taste Canada award!

6 Replies to “Zero Waste Sourdough Discard Banana Quick Bread”

  1. Barbette Curran says: Reply

    Congratulations on your book nomination for the Taste Canada Awards!

  2. So, you peel your overripe bananas and put them in a jar, then to the freezer? I was freezing stuff in jars and making sure lip was loose and leaving 3/4″ below lid until frozen, then tightening lids, for decades before signing up for you posts. However, I never thought to freeze bananas this way. I just put them in a whatever old plastic bag with skins on when they were overripe. However, one of my daughter’s likes to get one from the freezer and put it her smoothie cold/chopped up. So, I wouldn’t have thought differently, but last weekend I got out 3 from the freezer and left them thaw to make banana bread last weekend, but then they got pushed to the bag of the fridge by someone, and I got way busy this week, and now I have delayed further grocery shopping as that plastic bag that held the 3 of them, leaked and I have overripe banana liquid all over the lower shelves and my produce bins, and I am not too excited for the fridge clean-out project scheduled for Saturday morning. A jar would have save all that…..I think I learned from one of your recent posts, how acidic the liquid from over-ripe bananas is and how I could rub them on plant leaves to protect them from insects??
    I had to look up Jenga, so it was still an all men bro profession in sub-prime mortgage lending as 2015? I am not sure what CVS is?? something I don’t remember from the US, maybe just not in Colorado or NM. In BC, it is an uncommon but present in some suburbs of Vancouver, there is actually one down the street from where I live.

  3. *as late as 2015*. Gotta proof-read more especially at 11 pm.

  4. Made this and it turned out great! So happy to find another tasty use for starter.

  5. I often just toss my bananas in the freezer whole, i.e. with the skins on. They fit into those spaces between jars. But yes, they need to be placed into a tall jar for thawing in the fridge after that to prevent the kind of disasters Susan mentions. And you can smash them up with the skins on (some or all of) the organic ones for banana bread. A fork won’t do the job but a bit of work with scissors or a knife will do if you don’t want to use an electric mixer.

Leave a Reply