How to Dehydrate Sourdough Starter

If you’re new to sourdough, you may be wondering why you would want to learn how to dehydrate sourdough starter. But there are so many reasons! And they go beyond not being able to take your starter with you on vacations. 

The primary motivation for doing this, for me, is that I’m always at risk of forgetting to hold back starter after I feed it, and baking it all into a loaf of bread. So I need some backups.

Another really good reason it that it’s the easiest way to share. Got a friend who wants to try sourdough? All she needs is a teaspoon of dehydrated sourdough starter, and she can get started any time she wants!

It’s also great for shipping to friends who are further away. Not only because it’s stable, but because you only need to ship a teaspoon, it can fit in a regular letter envelope.

Why Dehydrate sourdough starter? 

The first and foremost reason to dry your starter is to preserve it, as discussed above. 

But it’s not the only reason. In fact, this is an excellent way to use your sourdough discard without wasting it. 

Once it’s dry, you can blend it into powder, and use it for much more than having a backup starter in long term storage. 

As How to Make Sourdough on Instagram talks about, you can blend your dehydrated starter into powder, and use it as fermented flour. 

This is great for thickening soups, making pasta, and many other uses. 

Dehydrating sourdough starter basics

Drying your sourdough is really easy to do. Really easy.

All you need is starter, and a dehydrator.

With that said, it is best to have a dehydrator. You can use your oven, either by heating it on a low setting briefly or if your oven has a pilot light, simply relying on the heat from that. But a dehydrator is faster, easier, and less prone to failure. 

The basic process is to feed your sourdough starter, then spread it thinly onto a dehydrator tray before it reaches its peak, since the warmth of the dehydrator will cause the the starter to continue to mature before it dries.

Once the starter is dry, you can seal your starter into an airtight container until you’re ready to use it.

How long does dehydrated sourdough starter last?

Dried sourdough starter will last until the microbes are reawakened. Which means that as long as it’s in an airtight container where moisture can’t get to it, it’s likely to last for a very long time. In fact, scientists have found 5,000 year old yeast microbes in Egypt, which they have successfully reawakened.

For shorter term storage, I use a jar with a rubber gasket to keep in the cupboard.

For longer term storage, I use my Anova vacuum sealer to vacuum seal the dried starter.

How long does it take to dry sourdough starter?

There are a number of factors that influence how long it will take your get your starter dry:

• How thick is it spread?
• The temperature at which you dry it
• The humidity in the room you’re drying it in

That said, the typical time range is 4-8 hours.

Pro tip: You may need to flip the sourdough starter over half way through drying, as it can be difficult to spread thinly enough for it to dry through without developing a dry skin that seals the rest of the starter off from the airflow.

How to dehydrate sourdough starter

1. First, feed your sourdough starter a 1:1:1 ratio. In other words, if you have 100 grams of starter, feed it 100 grams (by weight) of flour, and water each. 
2. Leave starter in a warm place, such as your kitchen counter top, to activate for about 2 hours, until you start to see bubbles. This will let you know that fermentation is happening. You want active starter, but you don’t want it at its peak activity, when you would normally use it for baking.
   
   You don’t have to worry about getting the activity perfect. Just get it active, but don’t let it fully consume the carbohydrates.
3. Once the starter is fed and active, Spread a thin layer on the fruit leather tray of your dehydrator.
   
   You can also use parchment paper, cut to fit your trays, or a silicone mat.
4. Turn dehydrator setting to 110º.
   
   
5. Let dry for about two hours, then check starter. If it’s dry on top, but still wet underneath, use a spatula to turn starter over, and let it dry another 2 hours.
6. Check again, flipping and drying as needed if there are more wet spots.
   
   
7. Once starter is dry, you may peel it off the tray and break it into small pieces, then store it as it is, or use a blender or food processor to pulverize it.

I prefer to blend it, as that makes it a little simpler to rehydrate.

How to rehydrate dried starter

Okay, so drying it is easy. But what about getting it ready to use again? 

In a glass jar or bowl, stir together:

• 10 grams of dried sourdoughs starter, (about a teaspoon, or a couple of dried starter chips)
• 50 grams of white flour (use all purpose or bread flour)
• 1 teaspoon of granulated sugar
• 60 grams of warm water

Cover with a loose lid or towel, and let sit at room temperature for 24 hours

Stir it up, and let sit for another 24 hours

On the third day, Add an additional 60 grams of flour, and 60 grams of water

Let sit another 24 hours.

At this point, you can feed again, and use on your normal feeding schedule, keeping it in the refrigerator between uses.

But keep in mind that it may be sluggish at first, and take as many as five or six feedings of your starter to start to look bubbly and active like you’re used to seeing.

More sourdough recipes for you to enjoy: 

• How to feed sourdough starter
• Sourdough sandwich bread recipe
• Caramel apple sourdough cinnamon rolls from scratch

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