Sourdough starter begins as a simple mixture of flour and water left at room temperature, where the yeasts and bacteria in the flour (and some airborne organisms) can freely multiply, transforming the mixture into its own unique culture.
Anyone who has attempted to make their own starter from scratch knows how precious and delicate that fledgling culture can be. And once you diligently nurture it to robust health, you still need to feed it regularly with flour and water to keep it flourishing.
While a vigorous sourdough starter can withstand a couple of weeks between feedings if it’s refrigerated, there may come a time where you want to put your starter on a longer pause.
Perhaps you’re going out of town and won’t be able to attend to it. Or you want a convenient way to take it with you. Or you may want a maintenance-free backup starter, in case something goes wrong with your active version.
Whatever the circumstance, drying your starter and reconstituting it later is an easy way to put your hard-earned treasure on hold without killing it.
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How to Dry Sourdough Starter
The smaller the pieces of dried starter are, the more easily and quickly they’ll dissolve when you’re rehydrating them, so really crush them up. But don’t be tempted to grind them in a spice grinder unless it’s immaculate, since many spices have antimicrobial properties that could harm your starter.
1. Feed starter to make at least 1 cup. When it has doubled to 2 cups, spread 1 cup in very thin layer on silicone baking mat or parchment. (Refrigerate remainder in case something unforeseen occurs.)
2. Place mat or parchment in high-sided vessel, such as roasting pan. Drape thin kitchen towel or double layer of cheesecloth over top and tie string around pan to secure it (this will allow moisture to evaporate while preventing contamination).
3. Leave vessel in a cool, dry space until starter is completely dry, 2 to 5 days, depending on ambient humidity.
4. Break dried starter into pieces and transfer to zipper-lock bag. Crush bag to make pieces as small as possible (for quicker rehydration). Press excess air from bag and seal. Store in cool, dry place.
How to Reconstitute Dried Sourdough Starter
1. Combine 2 tablespoons of dried starter chips with ¼ cup tepid water. Cover loosely and let sit, stirring occasionally, until chips are dissolved, 1½ to 2 hours.
2. Stir in 1½ ounces of all-purpose flour, cover loosely, and let sit for 8 hours.
3. Stir in 1½ ounces of flour and 1½ ounces of water; cover loosely, and let sit for 8 hours. Repeat step for 1 or 2 feedings, until starter expands about 25 percent between feedings.
4. Discard all but 2 ounces of reconstituted starter. Feed remaining starter with 2 ounces of flour and 2 ounces of water. Repeat step for 1 or 2 feedings, until starter doubles between feedings. Once it doubles, you’re ready to make your levain.
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Buy NowHow Long Does Dried Sourdough Starter Keep?
Sources say that the dried sourdough starter can be kept indefinitely. I kept mine for 10 weeks.
At that point, the reconstituted starter required one more feed to double in size than a dried starter stored for just 5 weeks, which suggests that a dried starter will lose efficacy over time.
For this reason, I recommend storing your dried starter for no longer than a year. Since drying a starter is so easy, you can just begin again with a new batch.
