How to Rehydrate Sourdough Starter: A Step-by-Step Guide

Learn how to rehydrate sourdough starter to launch your sourdough baking journey. In this guide, we'll take you through the simple steps to bring your dehydrated sourdough back to its lively, active state.

Understanding Sourdough Starter

Before diving into the rehydration process, let's briefly understand what a sourdough starter is and how it works. Simply put, a sourdough starter is a mixture of flour and warm water that naturally becomes inhabited by wild yeast and bacteria. These microorganisms are what gives sourdough its characteristic flavor and leavening ability without the use of additional ingredients. A dehydrated sourdough starter is simply a dried form of this mixture, with the microorganisms lying dormant until reactivated (rehydrated.)

Gather Your Tools

To begin rehydrating your sourdough starter, you'll need:

• Dehydrated sourdough starter
• Unbleached all-purpose flour
• Warm water
• A clean glass jar with a lid
• A kitchen scale (optional but recommended)
• A spoon or spatula for stirring

How to Rehydrate Sourdough Starter

In your glass jar, mix 1 tablespoon of starter with 3 tablespoons of warm water. Stir until the dehydrated starter has dissolved. Let sit for about five minutes. Mix in 2 tablespoons of bread flour. Use the spoon or spatula to thoroughly mix everything together until you have a smooth, lump-free consistency. Ensure that all the dehydrated sourdough is fully incorporated into the mixture.

Let it Rest

Once mixed, cover the jar loosely with the lid or a clean kitchen towel. Allow the mixture to rest at room temperature, ideally around 70°F (21°C). This resting period gives the microorganisms in the sourdough starter a chance to rehydrate and become active again.

Feed Your Starter

The next day, check on your sourdough starter. You should start to see some bubbles forming on the surface, indicating that the wild yeast is becoming active. At this point, it's time to feed your starter. Add another 3 tablespoons of warm water and 2 tablespoons of bread flour. Cover and set back into a warm spot to rest.

Continue Feeding

For the next few days, continue to feed your sourdough starter at regular intervals, increasing the amount of water and flour by 50% each day. Make sure you do not go longer than 24 hours between feedings. Each time you feed it, discard half of the starter before adding fresh flour and water. This helps maintain the balance of microorganisms and prevents your starter from becoming too acidic.

Watch for Signs of Activity

As you continue to feed your sourdough starter, watch for signs of activity. It should start to rise and fall predictably between feedings, indicating that the wild yeast is thriving. You'll also notice a pleasant sour aroma developing, a sign that the fermentation process is well underway.

It is important to note that if your sourdough starter smells like alcohol or acetone, that means that it is “hungry” – increase the frequency of your feedings to every 12 hours until a pleasant sour smell returns.

If your sourdough starter starts to mold or smell strongly like vinegar, throw it away, thoroughly clean your jar, and start over.

If your dehydrated sourdough starter is taking longer than expected to rehydrate, try increasing the temperature slightly or feeding every 12 hours vs every 24 hours.

Ready to Bake

Once your sourdough starter is consistently doubling in size between feedings and has a strong, tangy aroma, it's ready to use in your bread recipes. Remember to always reserve a small portion of the starter to keep it going for future bakes.