Sourdough Starter: Care, Feeding, and Use

Sourdough starter is a symbiotic colony of yeast and bacteria that requires care and feeding.  Fortunately, both are pretty easy, and you only have to do it once a week.  All you need is a jar and a kitchen scale.

Sourdough starter

A vigorous fed sourdough starter

How to feed your sourdough starter

Once a week (set a reminder!), you will need to give your starter new food so that it won't die out.

  1. Remove your starter container from the refrigerator, pouring off any floating liquid.
  2. Stir your starter in its container.
  3. Pour 110g of starter into a measuring cup for liquids.  You will have some unfed starter left over.  Discard the leftover amount; place it into a new container to propagate; or use it in a recipe that calls for "unfed starter".

    sourdough-popovers

    Sourdough Popovers, an example of what you can make with unfed starter
  4. To the measuring cup, add 110g of unbleached all-purpose flour and 110g of lukewarm water and stir.
  5. Thoroughly wash your starter container under hot running water, being sure to scrape off all the crusty bits inside.  Don't use detergent.
  6. Pour the fed starter back into the container.
  7. Leave on the counter, with the lid slightly ajar, for two hours.
  8. Close the lid and return to the refrigerator.

How to use your sourdough starter

Plan 24 hours ahead from when you want to use your starter.

  1. Remove your starter container from the refrigerator, pouring off any floating liquid.
  2. Stir your starter in the starter container.
  3. Pour 110g of starter into a measuring cup for liquids.  This will allow you to continue your starter.  Follow the instructions for feeding your sourdough starter, as above (add flour and water, wash the starter container, return the starter to the container, wait two hours, and return it to the refrigerator).
  4. Pour another 110g of the original starter into a large jar.  Add 110g of unbleached all-purpose flour and 110g of lukewarm water.  Stir.  Leave the jar on the counter with the lid slightly ajar for 12 hours.
  5. After 12 hours, add 220g of unbleached all-purpose flour and 220g of lukewarm water.  Stir, set on the counter with the lid slightly ajar, and wait until it has doubled or tripled in volume.  This can take as little as 4 or as much as 12 hours.
  6. Use in your recipe that requires "fed starter".

    Extra-Tangy Sourdough Bread

    Extra-Tangy Sourdough Bread, an example of what you can make with fed starter

How to propagate your sourdough starter

The most fun part of maintaining a sourdough starter is sharing it with friends.

Sharing Sourdough Starter

Propagated sourdough starter, ready for sharing!
  1. When it comes to feeding time, follow the instructions for feeding your own sourdough starter, but also place 110g of starter in a separate, clean container for your friend.
  2. To your friend's container, add 110g of unbleached all-purpose flour and 110g of lukewarm water.  Stir.
  3. Leave the jar on the counter with the lid slightly ajar for 2 - 4 hours.
  4. Replace the lid and give it to your friend.  If you are not giving it away immediately, you can store it in the refrigerator for up to one week without feeding it again.  You might want to add a date to the container to show when it was last fed.

Troubleshooting

  • I went to feed my starter, and it has a thin layer of brown liquid at the top.  Is it ruined?

    • No.  That's alcohol, another fermentation byproduct.  Just pour it off.
  • My starter smells much sharper than when I put it into the fridge.  Is it ruined?

    • No, there's just a lot of vinegar in it.  Without delving too deeply, lactobacillus produces two primary acidic metabolites: lactic acid and acetic acid.  Lactic acid is what gives yogurt its tang, and it's mild.  Acetic acid is vinegar, and it's sharp.  Refrigeration suppresses production of lactic acid, so your starter will have developed more vinegar than it has developed yogurt-acid.  When you feed it and leave it at room temperature for a couple hours, it will dilute the vinegar and give the bacteria some time to produce lactic acid at room temperature.
  • I fed my starter twice to use in my recipe, but it's not bubbly.  Is it ruined?

    • Probably not.  This often happens if it has missed a feeding or if your kitchen is not warm enough.  After the two feedings (waiting 12 hours after each), if it hasn't reactivated, set aside 220g of the mixture, add 220g each of flour and lukewarm water, and return to the cleaned jar until it doubles or triples in volume.  If that doesn't work, repeat after 12 hours.  Sorry if this threw off your baking schedule.
  • I fed my starter four times at room temperature (and waited 48 hours total) like you instructed, and it's not bubbly nor increasing in volume.  Is it ruined?

    • Probably.  You will need to start over.  Sorry.
  • I took my starter out of the refrigerator, and it doesn't smell sharp or boozy — it smells putrid!  Is it ruined?

    • Yes.  You will need to start over.  Sorry.
  • My refrigerated starter has billowy mold on it.  Is it ruined?

    • Yes.  You will need to start over.  Sorry.

Did I miss anything?  Anything unclear?  Let me know in the comments!