How to Rehydrate a Dehydrated Sourdough Starter

April 7, 2025

UPDATED 8/10/2026: Aloha! Welcome to our new Rehydration Instructions page! It's the same information, just organized a little differently. Feeding schedule and amounts have NOT changed.

To go back to the old version click here.

Mahalo

HOW TO REHYDRATE (quick guide)

HOW TO REHYDRATE (with photos)

Tips for success

Use lukewarm filtered or spring water. Avoid cold or hot water.
Use unbleached, unenriched, organic flour for the best health benefits. (This is optional.) Good quality flour brands: King Arthur, Bob's Red Mill, and Kirkland.
Make sure the lid on your starter jar is not too tight. The starter will release CO₂ gas, and a tightly sealed container could burst. Tighten the lid all the way shut, then turn it back half a turn. The goal is to keep bad bacteria out and prevent mold but also allow the gases to be released.
The starter is ready to bake with when it's bubbling and "peaks" (the surface begins to flatten and the starter doubles or triples in size) within 4-6 hours after feeding.
Note: It will fall after it rises. This is normal.
Be patient. Starters may reactivate in as little as 3 days or as long as 1 week depending on its environment.

What you’ll need

☐ 10 grams Dehydrated Sourdough Starter
☐ 1 ½ cups Flour All-Purpose Flour or Bread Flour
☐ 7 oz Water Filtered or Spring Water
☐ 16 oz Glass Jar & Lid
☐ 34 oz Glass Jar & Lid or bigger
☐ Measuring Spoons and Cups
☐ Rubber Band (optional)

Instructions

DAY 1

Step 1:

In a clean 16 oz glass jar (or bigger), add 10 grams of sourdough starter and 1.5 Tablespoons of water. Let it sit for 1 hour, so the starter softens.

Step 2:

After 1 hour, stir well to combine.

Add 1 Tablespoon of flour.

Mix until all flour is dissolved. Cover loosely with a lid. Let it sit in a warm spot for 24 hours (70-75℉ is ideal).

DAY 2

Step 1:

Add 2 teaspoons of water and 1 Tablespoon of flour to the starter.

Step 2:

Mix until all flour is dissolved.

Step 3:

Cover loosely with a lid. Let it sit in a warm spot for 24 hours.

8 hours later:

It should start to bubble after this feed, keep going!

DAY 3

Step 1:

Add 2 teaspoons of water and 1 Tablespoon of flour to the starter.

Step 2:

Mix until all flour is dissolved.

Step 3:

Cover loosely with a lid. Let it sit in a warm spot for 24 hours.

DAY 4

Step 1:

Add 1/4 cup water and 1/3 cup flour to the starter. Mix well until flour is dissolved.

Step 2:

Cover with a loose lid. Let it sit in a warm spot for 24 hours.

Optional: Place a rubber band on the jar to mark the starting level of the starter, so you can see how much it rises.

4-6 hours later:

You should see more bubbles & growth. If the starter “peaks” within 4-6 hours after this feeding, you can stop here and start baking with your starter.

If not, continue to day 5. You’re getting close!

"Peak" - is when the starter is double or triple in size and the surface of the starter begins to flatten within about 4-6 hours after feeding. After it peaks, the starter will slowly fall back down to the starting level.

Day 5:

Step 1

Transfer your starter to a bigger jar (34 oz or bigger).

Step 2

Add 1/2 cup of water and 1 cup of flour to the starter. Mix well until flour is dissolved.

Cover with a loose lid. Move the rubber band on the jar to mark the starting level of the starter, so you can see when it doubles. Let it sit in a warm spot and keep an eye on it.

4-6 hours later

Your starter should be actively bubbling and "peak" within about 4-6 hours after feeding.

Congratulations! You successfully reactivated your starter and are ready to bake!

What if it's not ready yet?

If your starter isn't bubbling and rising as expected after the feeding on Day 5, don't worry! Timing can vary depending on your kitchen’s environment. It doesn't mean you did anything wrong. Consider the temperature. Remember, if it's really cold, it will take a little longer to rise.

Here's what to do next:

On Day 6 (24 hours from the last feeding), discard half of the starter (throw in trash) and follow the Day 5 feeding. Repeat this every 24 hours until it’s showing signs that it's ready.

AFTER IT'S ACTIVE:

Maintaining the starter:

You can now begin maintaining your starter with a regular feeding schedule.

Once the starter is successfully reactivated, it can be stored at room temperature (if you bake daily) or in the refrigerator (if you bake weekly).
For regular feedings, use a scale and weigh ingredients in grams. Most recipes will be in grams since it is more accurate.
Regular feedings should be ratios of 1:1:1, 1:2:2, 1:3:3, 1:5:5, 1:10:10, etc. of starter, water, and flour. Keep in mind: the larger the ratio, the longer it will take to peak.