How to Dehydrate a Sourdough Starter

Why Dehydrate a Sourdough Starter

Are you going on a long trip? Do you want to transport your starter someplace else? Are you tired of caring for and feeding your live starter? Do you want a back-up in case you kill off your live starter? Whatever the reason, sometimes, you must make your starter dormant. In this post I will teach you how to dehydrate a sourdough starter.

A Few Words about Starter Science

Sourdough starter is a living, breathing, eating microorganism. Technically, it’s millions, if not billions of microorganisms grown from hundreds of different yeast spores that naturally reside in air, in wheat flour, etc. You probably worked hard to cultivate all those lovely organisms by growing your sourdough starter from scratch (a true test of patience!). Then, you proceeded to care for it for years through feeding and watering (flour and water feedings) just as if it were a family pet. And in return, it has loved you well by producing some gorgeous sourdough bread. Now it is time to take it up to the next level…dormancy!

Dormant Yeast

Dormant yeast is just that – Dormant. Not dead, just in a deep slumber. For any bread baker, the concept of dormant yeast should not be foreign. Have you ever baked with store-bought yeast? Yes? Well, then you have used a dehydrated yeast to produce yummy breads. When a factory produces shelf-stable yeast, they dehydrate, package, and ship it to stores. Whereas, fresh yeast and sourdough starter do not have long shelf lives. You must store fresh (cake) yeast in the refrigerator and use it within days. On the other hand, you must feed an active sourdough starter in a warm environment (i.e. your kitchen counter) every 12-72 hours (dependent on kitchen temperature). You may stretch those feedings if you store your sourdough starter in the refrigerator.

lets geek out for a moment

How can yeast be dehydrated?! Doesn’t living organisms die when dehydration happens? Well, normally, yes. We all have had that parched taste in our mouth, which elicits the survival response to drink a glass of water. All living things need water to survive, or do they? Actually, yeast spores are uniquely adapted to dry environments and have a survival mechanism to prevent their “death” for a long, dry period. Therefore, yeast spores resident in your sourdough starter can survive dehydration for a long period of time.

What tools are needed to dehydrate a sourdough starter?

You need four helpful tools before you attempt dehydration.

1. A Half Sheet Pan. This ensures a hard backing so you can smear your starter evenly. I like the Fat Daddio’s brand of pans – I use them in my own bakery and they are rigid, strong and durable.

Second – A large piece of parchment paper. I personally like these pre-cut sheets that fit neatly into a half sheet pan. I suggest you do not use a silpat (silicone liner) as it may contain residue.

Third – An offset spatula (frequently used for cake decorating or serving) is great for smearing the starter evenly over the parchment paper.

Fourth – An air tight glass jar. I am partial to mason-type jars with flip top lids. They are solid glass jars, they close securely and are easy to open.

So, NOW, How to Dehydrate your Sourdough starter

Ten Steps to Dehydrating A Sourdough Starter

1. Have an active starter (no active starter, check out this post to create yours).
2. Feed Your Active Starter at a 1:1:1 ratio (mix together active starter + flour + water in equal parts).
3. Allow Your Active Starter to Double in Volume (should double within 6-8 hours indicating it is active and healthy).
4. Prepare a sheet pan with clean parchment paper.
5. Smear the active starter across the parchment paper using an offset spatula
6. Turn the light on inside your oven to create a warm spot.
7. Place the sheet pan with the parchment paper smeared with active starter into the oven. TIP: You may want to place a piece of sticky tape or post-it note over your “start” button so you don’t accidentally preheat the oven!
8. Every 12 hours check your starter to see that it is is dehydrating (edges will appear dry while the center continues to be wet). Turn the pan 180 degrees and place back into the oven.
9. Leave your starter in the oven with the light on until it is completely dry (edges turn up and begin to crack and the center is dry to the touch).
10. Break your starter up into pieces and store it in an airtight container for up to one year.

Frequently Asked Questions About Dehydrated Sourdough Starter

1. How long does it take to dehydrate a starter? Well, that depends, it might take a few days or even a week or more. For instance, if you live in say, Florida, where relative humidity is 90%, dehydration will take longer than say, if you live in the Arizona desert where relative humidity is less than 10%.
2. Do I need to cover the starter while it is dehydrating? No, it does not need to be covered.
3. How do I store my dehydrated starter? Store your dehydrated starter in a dry, dark, area in an air tight jar.
4. How long can I store my dehydrated starter? It can be stored for up to one year.
5. How do I rehydrate my dehydrated starter? Check out my next post to learn how to rehydrate the starter.

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