5 Ways To Strengthen A Sourdough Starter: Give Your Starter A Boost

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If your sourdough starter is a little sluggish, it might need a boost to get it consistently doubling.

Perhaps it's been a little neglected and needs a refresh or perhaps it's just not performing as you'd like it to.

Here are 5 ways to strengthen a sourdough starter.

Sourdough starters are fairly resilient collections of yeast and bacteria.

Once mature, they will generally suffer through a bit of neglect - but sometimes it can be a bit of a struggle to get them to mature.

If you have had no luck troubleshooting your starter, it might be time to look at ways to give your sourdough starter a boost!

How Does A Mature Sourdough Starter Behave?

A sourdough starter that has "matured" will consistently double it's volume around 4-6 hours after it's fed.

It will have bubbles on the side of the jar, as well as breaking on the top.

Strong sourdough starter - this photo shows the same jar of sourdough starter 3 times. You can see the strong bubbles on the side of the jar and the second two photos are from above and show the thick, strong sourdough starter.
A mature sourdough starter - it will look spongy as it doubles its volume.

The million dollar question everyone asks is "when will my sourdough starter be ready to bake with"?

And there's no single answer - it can take 7 days, it can take 4 weeks.

As a rule of thumb, most will be starting to be ready around 14 days - but even then it is still very young and has some growing to do!

Patience really is the key to becoming a good sourdough baker!

There is more information on how to know when your starter is ready to bake with here. And if you're wondering how your sourdough starter rises and falls, then you can learn about the science of sourdough starters here.

5 Tips to Strengthen Your Sourdough Starter

These tips will work to strengthen your sourdough starter if:

  • your starter has been a bit neglected (left in the fridge unfed a bit too long) or you've skipped a few too many feeds on the counter;
  • you've been growing your sourdough starter for a few weeks and it's just not doubling consistently;
  • your starter is constantly smelling like nail polish remover, even after a feed.

Boost Your Sourdough Starter With Oxygen

One of the easiest ways to strengthen your sourdough starter is to make sure it's getting enough oxygen. You can do this by:

  • making sure you don't have the lid screwed tightly on your jar - just cover with a piece of paper towel or coffee filter secured with an elastic band.
  • stir your starter in between feedings - try stirring it twice in between feedings and really give it a chance to get oxygen into the mix.

    This will help to activate your starter without too much effort.

Feed Your Sourdough Starter Superfood

If you have created your sourdough starter from a white, processed flour, it will really benefit from having a boost of rye flour.

Rye flour is like a superfood to your sourdough starter and it will help to strengthen it fairly fast. In fact, rye flour starters perform notoriously well.

Rye flour will help to make your starter more sour.

To boost your sourdough starter with rye flour, substitute half your normal flour with rye flour at each feeding for a few days and you should see a noticeable difference in your starter's activity level.

Freshly milled whole wheat flour is also very beneficial to your starter if you have access to it and can help to increase the wild yeast in your sourdough starter. For more information on feeding your sourdough starters different flours, check out this guide.

Rye sourdough starter shown from the side of the jar. There is a an ear of wheat and a red and white dish cloth in the photo too.

Keep Your Sourdough Starter Warm

Temperature is so important when establishing a sourdough starter, and also when trying to strengthen a weak sourdough starter. A sourdough starter that is being kept in cooler temperatures (below 70F/21C) will not colonise and thrive as well as a starter that is kept above 75F/24C).

You'll find over 20 ideas to keep your sourdough starter warm here.

Feed Your Starter More Often

It's as simple as it sounds. If your starter is sluggish and not behaving as you'd like, feed it more often - even up to 3 times a day if you really want to get it going.

Remember you need to discard half each time you feed your starter.

Feeding it 3 times a day isn't usually necessary for more than about 2 days - after that you should go back to once or twice a day (or you will risk overfeeding your starter).

If your starter continually produces hooch, it's a sign that it's hungry. It may mean that you need to increase the amount you're feeding it, rather than the regularity.

Try doubling the amounts of water and flour you are feeding your starter each time - so feeding at a 1:2:2 ratio.

Keep Your Starter At A Lower Hydration

If your sourdough starter seems to be a little thin, it can be hard to see if it's actually bubbling as the bubbles will escape.

A thinner starter will also not have the big bubbles on the side of your jar.

In order to strengthen your sourdough starter try and give it flour only for one or two feeds. This will make the mixture stiffer.

If your starter is quite runny, it should be easy to stir the extra flour into the mixture. If it seems a little stiff, it will loosen up as it eats and ferments the flour.

Once you've done one or two feeds of flour only, your starter should be thick enough and you can go back to normal feedings of flour and water. You should also notice your sourdough starter has larger bubbles.

Boost your sourdough starter by keeping it at a lower hydration - this photo shows a jar of sourdough starter being held in a hand. It has large, deep bubbles up against the glass of the jar.
A sourdough starter kept at a lower hydration will be quite thick and spongy. You'll need to use a spoon to get it out of the jar as it won't be "pourable".

If you're concerned that feeding your starter flour only will upset it's ratio - don't be. If you need your starter to be at 100% hydration for a recipe, you can make it that.

Once your starter is back on track, just put a tablespoon or so in a jar and then feed it equal parts flour and water - you'll then have a 100% hydration starter.

Totally Refresh Your Starter

If you are really seeing no consistent activity from your starter, you can give it a complete refresh. This will generally get your starter going again after a period of neglect or even overfeeding.

  1. Put 10g of your starter into a clean jar (you can discard the rest).
  2. Feed this 10g of starter with 25g of flour and 25g of water and stir in really well, remembering you want as much oxygen in the mix as possible.
  3. Cover loosely and leave for around 6 hours. By this stage you should see some bubbling starting to happen.
  4. After 6 hours, add another 25g flour and 25g of water, stirring really well to get that oxygen into the mix. Cover again and leave for another 6 hours.
  5. After 6 hours, discard approx half your mix so there's 50g left in the jar and feed as per normal (I recommend 50g of flour and 50g of water) - you'll be able to feed normally from now on, discarding half each time.

Frequently Asked Questions

Can I add sugar to my sourdough starter?

You can but there really is no need to. Sugar will give the yeast more to feed off, however this will not necessarily strengthen your sourdough starter. I would keep the sugar to add to your loaves - unless you are trying to create a sweet sourdough starter.

Why is my sourdough starter bubbling but not rising?

In the first few weeks of creating a sourdough starter, it is possible that your starter will bubble, but not actually rise (as in double). This is fine in the early stages of sourdough starter establishment. It just means that the bacteria in your jar are fighting it out for supremacy. Once the good bacteria win the fight, you'll see that your starter begins to double. It's very normal for a sourdough starter to bubble, but not rise, for a number of days in the early stages. Just keep going.

Should I stir my sourdough starter?

Absolutely. As mentioned above, stirring is a fantastic way to get oxygen into your sourdough starter which is essential for its growth.

Should I add pineapple juice to my sourdough starter?

No! There is absolutely no need to add pineapple juice to your sourdough starter. This will change the acidity in the jar. Just stick to flour and water (along with the tips in the post above).

Can you feed a sourdough starter different flours?

Yes you can. It's a good idea to add rye to give your starter a boost (if you think it needs it). If you are swapping flours (like swapping from all purpose to whole wheat or vice versa) understand that your sourdough starter may go through a little dormant period while it adjusts to the new food source. It will recover, but it might take a few days. Unless you are unhappy with your sourdough starter's progress, it's generally better to stick to the same flour for each feed to maintain a consistent starter.

Will the water I feed my sourdough starter make a difference?

Absolutely - the quality of the water you feed your sourdough starter is very important. You should avoid distilled, reverse osmosis and chlorinated water. You'll find a full guide to the right water for sourdough starter here.

Further Reading

  • Need a name for your sourdough starter? You'll find over 101 suggestions here.
Sourdough Made Easy Ebook

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19 Comments

  1. Thank you for this very helpful explanation. ive been baking sourdough for over a year now and I had no idea about any of this.

  2. Trying to boost the activity of my starter...it was doubling, but not many bubbles in the starter. It NEVER achieved the float test. So I fed it, then stirred it an hour later. Set the timer and stirred it again, and then once more before I went to bed. OMG, you were right, oxygen is the key! That and I loosened the lid on my jar produced a starter that tripled and was riddled with bubbles. You. Are. A. Genius.

  3. Thank you so much for sharing all this information!!!! It’s been THE Biggest help!!! My chickens are Nucking Futs over the starter discard!!! Thanks again!

  4. Awesome - I have been feeding my starter for weeks now and it was just not strong enough. After reading this page, I added 1 tbl spoon of Rye flour to my 200ml starter, no water, and within 6 hours I had a starter that doubled to 400ml. Thank you

  5. I grew up in the San Francisco Bay Area, and love the sour taste of Fisherman’s sourdough bread. I can’t get that sour taste. What tips would you offer to try to get that great sour taste?

  6. I do so rarely (more like never!) leave comments but this article was so helpful. Was thinking of giving up on my starter yesterday. The article from another blog that I followed does not mention as much about the hooch… yours is perhaps less wordy but somehow more informative!
    Now I feel like keeping at it again… thanks for the tips. 🙂

  7. Hi Kate,
    Thanks so much for all your information and handy hints. I've been baking sourdough since the start of Covid, but I'm always looking for ways to improve my "olive & thyme" and "multiseeded" boules (which are pretty darn good anyway).
    This time, in an effort to improve the strength of my starter, I'm gonna leave the lid off my jar whist it's in the fridge plus I'm gonna give it a good stir or two, in between its weekly feeds.
    Thanks again, Kate! 🙏

    1. Oh wow Avon, they sound like delicious flavor combinations! Love hearing about your sourdough journey and quest for the perfect loaf xx

  8. Thank you so much for all the wonderful information you have provided!! I am so thankful to have found Pantry mama!

  9. Your suggestions saved "Thor," my beloved 3.5 year old starter who was really struggling after some neglect! Thank you!