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My Sourdough Starter Is Slow, What Should I Do?

A recurring problem many sourdough fans face is that their starter slows down, or it loses it characteristic flavor. This is relatively uncommon in commercial bakeries because they use their starter on a daily basis, and because the starter is used so frequently that the acidity of the starter stays under control.

A sourdough starter is a symbiotic relationship between one of 3 strains of yeast and one of 5 strains of lactobacillus bacteria. (Please note, as more research is being done, the number of both organisms that are found in viable sourdough is growing.)  The lactobacillus bacteria produce a number of antibiotic compounds that protect the starter from invasion by other organisms. The bacteria also increase the acidity of the starter, so most types of yeast cannot survive the acidity of the starter.

If the acidity is too high, the starter will dissolve the gluten in flour, which causes problems in making wheat based breads. If the acidity gets a bit higher, the yeast will die.

Bakers yeast cannot survive more than a few refreshments in a healthy starter, which is why we strongly encourage you to not use bakers yeast to start your starters, or with them to make bread. We talk about it in the "Starting a starter" post.

When your starter slows down, or loses its characteristic taste, you need to reduce its acidity and revitalize it.  Dilution reduces acidity.  And larger feedings encourage yeast activity.

I do this by putting 2 TBSP (60 grams) of the slow starter in a clean stainless steel bowl, whisking in 1/4 cup (60 grams) of water, and then whisking in 1/2 cup (60 grams) of the plainest white flour I can find.

In the section on starting a starter we encouraged you to use organic, stone ground, unbleached whole wheat or rye flour to start a starter because these flours contain more of the organisms we want to encourage. However, in this case we are trying to revive a starter, not create one. If you use a flour with lots of healthy organisms on it, you might wind up with an active starter - but not the one you started with and wanted to revive.

Some people worry about the possibility of starting a culture instead of reviving one that they sterilize the flour they use to feed the slow starter. Unless you have a starter that has been ignored a long time and looks dead, I wouldn't worry about this possibility. However, if you are very worried about losing the starter, you may want to think about sterilizing the flour and water you are using to revive the starter. You can do a reasonable job of sterilizing the flour by boiling the water you will use and pouring it over the flour and stirring the mixture. You can also bake the flour in the oven at 250F or so until the flour is hotter than boiling water (let it cool before you use it, of course). Some people use a microwave oven to heat the flour, but microwave ovens tend to heat unevenly so I am not a fan of this approach.

After twelve hours or so, your starter should be fairly lively. But the revival isn't over yet - whisk in 1 cup (240 grams) of water and 2 cups (240 grams) of additional flour. This time, the starter should take off much more quickly. Check it in 3 hours or so.

If your starter still isn't fast enough, repeat this procedure, at the paragraph above that starts, "I do this by putting 2 TBSP...". It is a rare starter that won't revive after one or two cycles through this procedure. I would not go through more than 4 cycles. Uncommon as it is, at some point you have to decide that starting a new starter would be easier than trying to raise the dead.

If, like me, you hate throwing away starter, you can use the rest of the starter to make pancakes, waffles, muffins, cupcakes, or pizza shells. More often than not, a really slow (or dead) starter is very acidic and will work well with baking soda.

2 thoughts on “My Sourdough Starter Is Slow, What Should I Do”

  1. I’m trying your method. After adding the 240 water + 240 flour, my starter has bubbles but isn’t rising. Should I start over with 60 + 60 + 60 after three hours or give the 240 + 240 a full 12 hours? My starter is gummy and smells heavy of flour.

    1. Hi Jessica,
      Not knowing the history or current condition of your starter makes it difficult to offer clear and unambiguous advice, so I’ll offer observations and generalities for you to tailor to your starter.

      Was your starter healthy at some time in the recent past? If so, it should be easy to revive! If not, perhaps the advice on reviving your starter might be more appropriate for your starter, or even our page on reviving a neglected starter. If you’ve never been happy with your starter, you might look at our information on starting a starter and just start over.

      Assuming that your starter was recently healthy and you were happy with it, it’s worth remembering that sourdough starter isn’t a chemical reaction like adding baking soda to vinegar. It is a biological entity, and it takes time to respond. I wouldn’t expect most starters to rise in 3 hours. When you feed a starter you are reducing the concentration of yeast and sourdough in the starter. If the concentration is too low – as from feeding too often – you might not see much action. Feeding too often doesn’t help your starter. In general, I wouldn’t feed any starter more frequently than every 6 hours.

      Also, with biological entities, there are many variables. They slow down when they are cold and speed up when they are warm. A rule of thumb suggests that the rise time will double for every 10 degrees F the starter is cooler, and rise twice as fast for every 10 degrees F warmer the starter is. If your starter isn’t at room temperature, you might change that. For the purposes of our discussion, room temperature is 70 to 80F (21 to 27C).

      Bubbling is a good sign of life. If it is bubbling there is hope. Another factor is the flour you are using. If you are using cake flour, stop. Cake and pastry flour just aren’t suited for bread making. Whole wheat and rye flours tend to rise less than all-purpose and bread flour. What you’re getting may be fine, the final test is in the bread. If you are using an all-purpose or bread flour, the starter should rise. If it isn’t be patient, give it another feeding or two. Also, look for signs of rising on your container. Over the course of 12 hours some starters rise and then fall. However, when they do this, they leave residue on the sides of the container. You might pour your starter into a clean glass container and look at it 12 hours later to see if it rose when you weren’t looking.

      Hope this helps,

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