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Dehydrating and Rehydrating Sourdough Starter
Dehydrating Sourdough Starter
The long days of summer are known for many things, but baking sourdough bread may not be at the top of the list. Hot kitchens and vacations complicate the maintenance of the sourdough starter you have worked so hard to develop. You don’t want to toss it or just let it sit in the back of your refrigerator all summer, slowly acidifying to the point of no return. But there is an easy way to put your culture in “suspended animation” and bring it back to life when the bread baking bug bites again.
Dehydrating is easy, convenient, and the perfect long-term storage solution. It's also a great option if you plan on transporting your starter or sharing with friends. Dehydrating sourdough starter creates a shelf-stable starter with microorganisms held in an inactive/dormant state. In dehydrated form, the sourdough starter will last years. We had great success bringing back to life a 2-year-old dehydrated starter stored in a jar at room temperature. Within 5 days it was fully active and used to leaven bread.
Even if you don’t plan to take a break from baking, having some dehydrated starter on hand is still a good idea. If something accidentally happens to your starter, you will have a backup on hand. All you need to do to bring it back to life is to feed it with flour and water for a few days.
Time & Temperature
Dehydrate at 88 °F / 31 °C for 4 – 6 hours
Equipment
- Brod & Taylor Sahara Folding Dehydrator
- Brod & Taylor Silicone Baking Mat
- Spatula or bowl scraper
- Airtight container
Instructions
Before you begin:
Dehydrating sourdough starter will reduce the microbe population numbers, therefore it is best to start with a recently fed, healthy starter near peak activity. Doing so will set you up for better success when rehydrating. The more yeast and bacteria you start with, the more you are likely to be left with after drying, and the easier it will be to revive in the future.
Steps:
1. Spread the starter out on a silicone baking mat as thinly as possible. Use an offset spatula, bowl scraper, pastry brush, or any tool that will allow you to get a very thin layer. (Note: We found that 75 grams of 100% hydration sourdough starter spread very thinly covered one Brod and Taylor Silicone Baking Mat)
2. Place the silicone mat into the dehydrator and dry at 88 °F for 4 - 6 hours, or until completely dry. This may take more time depending on how thinly it is spread.
Spreading a thin layer of starter on a silicone mat
The dried starter in the dehydrator
Close-up of dehydrated starter
3. Break the dried starter into small pieces or grind it into powder for storage.
4. Store in an airtight container (glass jar, plastic bag, plastic container) out of direct sunlight and direct heat. Optional - the dehydrated starter may also be kept in the refrigerator or the freezer.
Jars of dehydrated sourdough starter sealed for storage
A single jar of dehydrated sourdough starter sealed for storage
Rehydrating Sourdough Starter
Time & Temperature
4 - 6 days with the Sourdough Home or Proofer set to 78 °F / 25 °C
Equipment
- Brod & Taylor High Capacity Baking Scale or Brod & Taylor Precision Scale
- Brod & Taylor Sourdough Home or Brod & Taylor Folding Proofer
- Small bowl or a jar
- Spatula
Instructions
A few days before you want to use your starter for baking, revive your dehydrated starter. Either the Sourdough Home or Folding Proofer can be used to keep the starter warm.
DAY 1
- In a small bowl or jar, mix 5 grams of dehydrated sourdough starter with 15 grams of 80 °F water.
- Allow the starter and water to sit for about 2 hours, or until the dried starter dissolves.
- Stir in 15 grams of flour.
- Cover and put in the Sourdough Home or Proofer at 78 °F overnight, or for 12 - 14 hours.
5 grams of dried starter
Dried starter dissolved in 15 grams of water
With 15 grams of flour added
DAY 2
There may not be visible signs of activity at this point.
- Without discarding any of what is in the jar, stir in 10 g of flour and 10 g of water.
- Return to the 78 °F Sourdough Home or Proofer.
DAY 3
You may begin to see signs of activity at this point such as small bubbles and a slightly sour aroma.
- Without discarding any of what is in the jar, stir in 10 g of flour and 10 g of water.
- Return to the 78 °F Sourdough Home or Proofer.
DAY 4
You should see clear signs of activity at this point. The starter will have risen since the last feeding and you will see bubbles.
Day 4 before feeding: signs of activity
are showing, bubbles are visible
- Discard all but 15 g of the starter.
- To the 15 g of starter add 30 g of water and 30 g of flour.
- Return to the 78 °F Sourdough Home or Proofer until the next day.
DAY 5
Your starter should be very active at this point. It will have doubled in size, be very bubbly, and smell sweet with just a hint of sourness. By Day 5 your starter will be very active. The time it takes to peak will have shortened from the previous days. In our experience, 7 hours after the day 5 AM feeding the starter had just about tripled in size.
IN THE AM
- Discard all but 15 g of the starter.
- To the 15 g of starter, add 30 g of water and 30 g of flour.
- Return to the 78 °F Sourdough Home or Proofer.
IN THE PM
- Check your starter around the 7-hour mark. If it has close to tripled in size, then repeat the same feeding as you did in the AM. If it has not yet peaked, let it go another hour or two before checking again.
- At this point, your starter should be active enough to bake with. (We had great success making a levain from the starter at this point that was used in the dough the next day.)
DAY 6
The starter should be fully active at this point.
How does rehydrating sourdough starter compare to starting a sourdough culture from scratch?
Is there an advantage to rehydrating a dried sourdough starter rather than building one from scratch? Yes. A side-by-side comparison of rehydrating dried sourdough versus building a starter from scratch showed a noticeable difference in the time to mature. From our experiments, we found the rehydrated starter reached a vigorous healthy state much sooner than the starter built from scratch. The rehydrated starter was close to tripling in size by Day 5, whereas the starter from scratch has only risen very slightly. The starter from scratch lagged behind the rehydrated starter until the Day 13 mark when they were both rising and falling predictably and showing the signs of the same activity level. Conditions were kept the same for each starter- same seed amounts, same feeding, and same temperature.
Day 4 comparison of starter made from scratch and rehydrated starter. The rehydrated starter is visibly more active.
Day 5 comparison of starter from scratch and rehydrated starter in the morning before the daily feeding.
Day 5 comparison of starter from scratch and rehydrated starter 7 hours after being fed in the morning.
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26 comments
Do I need to add the water tray for this?
Carrie – No, you do not need the water tray when rehydrating your starter. We recommend keeping a lid on your starter jar to prevent it from drying out, rather than using the water tray.
Thank you so much.
My husband and I are going to an inclusive plant based diet. Have you ever made sour dough with all whole wheat? Can you share the bread recipe.
Tammi – Yes, you can certainly make sourdough with 100% whole wheat flour. We don’t have a recipe on our website, but we plan to work on it in the future. You can make any of our sourdough recipes using only whole wheat flour. You may need to add more water, and the finished loaf might have less volume, but it should still work just fine. A good place to start may be our Seeded Sourdough recipe. It has half spelt flour and half bread flour. You can use all spelt flour or replace the bread with whole wheat. If you have further questions, please don’t hesitate to reach out to us at contact@brodandtaylor.com. We are always happy to answer baking-related questions.
When rehydrating a dehydrated starter, does the discard have to be thrown out like it does the first week when creating a starter from scratch, or can it be used in recipes?
Morgan – When rehydrating the discarded starter, you will begin discarding it on day 4. At that point, you can use the discard in a recipe rather than tossing it out. It will may not be strong enough to leaven bread (although it is possible it could be), but you can certainly use it in any sourdough discard recipe.
How much dehydrated starter powder do you save per bag? Say I want to share my dehydrated starter with family and friends-how do I know how much powder to put in each bag?
Connie – You can out as much or as little as you’d like. Our rehydration instructions only call for 5g of dried starter so that amount would be enough to get a starter going. Of course, you may want to do a slightly larger amount so there is extra in case they need it- maybe 10 to 15g.
Hi!! This guide has been SO helpful! I’m on day 5 of rehydrating, for the second feeding on day 5, do you discard down to 15g or just fees additional flour/water without discarding? Thanks so much!!
Elisabeth – We are happy to hear our article has been helpful! Yes, if you are doing the second feeding on Day 5, discard down to 15g and then feed it with 30g of water and 30g of flour.
I love this! I have the Sourdough Home which in addition to my sourdough starter, I use to culture small quantities of yogurt and buttermilk. Did I mention how much I love my SD Home! Sorry, on to the question. Can I dehydrate my other cultures to make backup starters? If so, at what time and temperature for buttermilk and yogurt.
Steph – Thank you so much for your comment! We’re thrilled to hear that you love your Sourdough Home! We don’t have direct experience with dehydrating yogurt or buttermilk cultures. We’ve heard of people attempting it with yogurt, but the results seem mixed. You might find some helpful information by looking around online, as others may have tried it successfully. Alternatively, you could experiment with small batches to see what works best. We’re sorry we can’t be more helpful on this topic, but we wish you the best of luck with your experiments!
Hi. How did you set day 6 as the day the starter is fully active? I just like to know the theory behind it.
Hi. What would you say is the criteria for determining when a rehydrated starter is ready to use? Most tutorials for rehydrating starter calls for feeding for about five days and I’m quite tempted to use it on day 3.
Kate – Great question! The reason we identify day 6 as the day the starter is fully active is based on observable signs that indicate a ripe starter. There will be a noticeable increase in volume a few hours after feeding, typically tripling in size. You should see plenty of bubbles on both the sides and top of the jar, and the starter will have a slightly sour and yeast-like aroma. If you scoop out a spoonful, it will seem light, a bit loose, and airy, with a web-like texture rather than stiff and doughy. When rehydrating a starter, the process happens faster than if you were creating one from scratch because you have a head start by introducing the microbes in their dried form. These microbes become active more quickly, allowing the starter to reach maturity in a shorter time frame. I hope this helps! Let us know if you have any other questions.
Tammy – The criteria for determining when a rehydrated starter is ready to use are similar to those for a freshly created starter. You should look for a noticeable increase in volume, ideally tripling in size. There should be plenty of bubbles on both the sides and top of the jar, a slightly sour and yeast-like aroma, and a light, loose, airy texture with a web-like appearance. Because a rehydrated starter can be ready to use much sooner than a starter created from scratch, it is entirely possible that your starter could be ready by day 3, as long as it meets these criteria.
Hi again. Thanks for answering my previous question. Can you share how many hours in advance you feed the starter before you use it in a dough? I need this wisdom for scheduling. I feel like the starter eight hours after feeding is the best, and I can tell a difference compared to when I use it after 12 hours. However, sometimes my laziness and indiscipline get in the way.
Kate – Kate – The time it takes for your starter to peak after feeding depends on two main factors: temperature and feeding ratio. Adjusting these can help fit your schedule. Cooler temperatures and higher ratios slow down fermentation, while warmer temperatures and lower ratios speed it up. If your starter peaks at 8 hours but you want it to last 12 hours, try adjusting these factors. Temperature: If you use the Sourdough Home, lower the temperature by 5 degrees. If you don’t have the Sourdough Home, feed your starter with cold water. You can also put it in the fridge when it’s close to peak to slow fermentation for a few hours without it becoming overripe. Feeding Ratio: Use a higher feeding ratio. For example, if you currently use a 1:2:2 ratio, try using a 1:4:4 ratio (1 part starter, 4 parts flour, 4 parts water by weight). A slightly past peak starter (maybe an hour or two past) is usually still good for baking, but avoid using it for leavening bread once it has collapsed completely, is very runny, and strongly acidic, as it won’t have enough strength for your bread
I am really amaze about dehydrated sourdough come’s back to life, like a real MAGIC! It really helps a lot for us!
On day 1, when adding flour it’s really thick. Should I add more water?
Nicole – It is normal to be a little thick after feeding on Day 1. It will become less thick as the days go on. If it seems so thick you are having difficulty mixing it or the flour is all hydrated, add a small splash of water.
What can I use if I don’t have a dehydrator? I do have your proofing box, and the Sourdough Home, both of which I love. Thanks!
Eric- So glad to hear you are loving the SDH and Proofer! You can leave the starter to dry at room temperature. Using the dehydrator is the most efficient way to dry your starter, but as long as it is spread very thinly, it will still dry without the dehydrator, but it may take longer. Be sure to check that no moisture remains before storing it.
Hi. I have two questions: 1. Is there a reason behind 5g of dehydrated starter + 15g flour + 15 water? So the water is slightly less than the flour? 2. What should I do if I want to make a sweet stiff starter? Should I follow your instruction until the starter is fully active, then following the instruction for making sweet stiff starter? Or do I create a sweet stiff starter from day 1?
Kate – Great questions—happy to clarify! We use 5g of dehydrated starter with 15g each of flour and water to keep things simple and close to 100% hydration. Technically, in this case, the water is slightly less than the flour at the first feeding, but the difference is minimal and doesn’t affect the outcome, so we keep it straightforward. Yes, the best approach is to follow the rehydration instructions until your starter is fully active. Once you have a robust, active starter, then you can transition to making a sweet stiff starter.