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

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

This post may contain affiliate links, which means if you click through and purchase, I may receive a commission at no cost to you. As an Amazon Associate, I earn from qualifying purchases.

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 give 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 (I prefer King Arthur Bread 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

Place a clean glass jar on your scale and measure 25 grams of dehydrated starter into the jar.

Add 50 grams of warm, not hot, filtered water and stir gently until the flakes soften and dissolve as much as possible. It is perfectly fine to crush larger pieces with your spoon to help them break down.

Let the mixture sit for 30 to 60 minutes so the dried starter can fully absorb the water and begin rehydrating.

After that rest, add 50 grams of bread flour and stir until everything is fully combined and smooth. The texture should resemble thick pancake batter or a soft pudding consistency. Make sure no dry flour remains at the bottom of the jar.

Loosely cover the jar with a lid resting on top or a breathable cover and place it in a warm spot around 70 to 75 degrees. Allow it to rest for 24 hours.

Day Two: First Feeding

After 24 hours, you may see bubbles forming on the surface, or you may see very little activity, and both outcomes are completely normal.

Discard all but 50 grams of starter, then feed it with 50 grams of warm water and 50 grams of bread flour. Stir thoroughly until smooth and loosely cover again.

Continue Feeding

For the next several days, continue feeding once every 24 hours using the same ratio of 50 grams starter, 50 grams water, and 50 grams flour.

Before each feeding, discard down to 50 grams so the amount stays manageable and properly nourished. Consistency matters more than increasing quantity, so resist the urge to grow it too quickly.

To avoid wasting your discard, you can try these Sourdough Discard Recipes which are a great way to learn how sourdough starter works even before tackling your first official loaf.

Within three to five days, your starter should begin doubling in size within several hours of feeding and developing a pleasantly tangy smell. At that point, it is strong enough to bake with.

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, turn a pinkish color, or smell strongly like vinegar, throw it away, thoroughly clean your jar, and start over.

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.

Here is my favorite Classic Sourdough Loaf Recipe that makes the perfect loaf every time.

A Couple Notes

It is hard to really “mess up” sourdough starter. As long as you are feeding it regularly with good-quality flour and warm water, it should be just fine. Continue discarding and feeding no less than once per day for 2-3 weeks before giving up.

Some starters may be more sluggish than others, and that is perfectly ok. Even a sluggish starter can become a healthy, active stater with the right TLC. If your starter does not show signs of activity, increase feedings to twice per day.

Sourdough breadmaking has been around for many, many years – long before we had fancy tools or even central heating and air conditioning! Trust the process – you can totally do this.

If you need help, feel free to reach out to me on Instagram or via email lynsey@paulinemanor.com