How To Revive Frozen Sourdough Starter?

Freezing sourdough starter is a good idea if you're looking for a long term storage solution. Reviving a frozen sourdough starter is not difficult but may require some patience. The best way to breathe life back into it involves a few simple steps that can ensure a vibrant and healthy starter ready to leaven your bread to perfection. Understanding how to revive frozen sourdough starter can be the key to preserving its robust flavour profiles and maintaining its microbial diversity, ensuring a thriving and active culture for your baking endeavours.

Jump to:

• Does Freezing Affect Sourdough Starter? 
• How To Freeze Sourdough Starter?
• How To Defrost A Frozen Starter?
• Reviving Sourdough Starter
• What To Do With All That Sourdough Discard?
• Extra Tips For Best Results
• How Many Feeds Will It Take To Revive My Frozen Starter?
• Can I Refreeze A Previously Frozen Starter?
• Christmas Sourdough ebook
• Other Sourdough Tips & Tricks
• Popular Sourdough Bread Recipes To Try

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Does Freezing Affect Sourdough Starter? 

The good news is that a healthy sourdough starter is highly resilient and can withstand cold temperatures. Even in the coldest freezers, the lactic acid bacteria and wild yeast present in the sourdough culture can survive. While some yeast may die off during the freezing process, the remaining dormant yeast in the culture is sufficient for revival upon defrosting.

There is no permanent damage caused by freezing a sourdough culture, as the yeast colony will quickly reestablish itself once the starter is refreshed. Although sourdough starters thrive in warm temperatures (ideally 24-27°C), freezing is a safe option. 

But for successful freezing, you must avoid freezer burn and ice crystals forming on the surface, so consider double bagging for added protection.

How To Freeze Sourdough Starter?

For a full method and lots of tips and options, visit our dedicated article on How To Freeze Sourdough Starter. Here are the main tips to remember: 

• Never freeze a new starter, that doesn't yet have an established colony of yeast. 
• Feed your starter and let it double in volume before freezing it. An active sourdough starter will be quicker to revive after thawing. 
• For convenience, divide your starter into small portions, and freeze them in moulds (like ice cube trays or silicone mini cake moulds) or freezer-friendly bags and label them with a date and amount. Double bag them to protect the starter from freezer burn. 
• Frozen starter can be kept in the freezer for up to a year.  

How To Defrost A Frozen Starter?

1. Take a portion of your frozen sourdough starter out of the freezer, and place it into a clean jar. 
2. Cover the glass jar with a lid loosely and leave it at room temperature to thaw, and come to room temperature (it may take 3-5 hours depending on the amount of starter as well as temperature). 
3. You will find that your sourdough starter is runny and sticky.

Reviving Sourdough Starter

1. Find a warm spot in your kitchen where the sourdough starter can rest and develop. Ideally, the temperature should be around room temperature, between 24°C and 28°C (75°F and 82°F). This warmth helps stimulate the fermentation process and encourages the starter to become active again. We have tips on how to keep sourdough starter warm, especially in the cold winter months, when room temperature drops.
2. In a small bowl, mix equal parts of flour (such as bread flour or all-purpose flour) and luke warm water. Stir the mixture well until thoroughly combined. Mix it in with the defrosted starter and leave the mixture for 12 hours before feeding again. 
3. Continue with regular feedings every 12 hours. Discard a portion of the starter (or use it in delicious sourdough discard recipes) and feed it with equal amounts of flour and water. Observe the signs of activity, such as bubbles and a slightly tangy aroma, indicating that the starter is coming back to life. We find it typically only takes 2-3 feeds to revive the starter and see the live yeast in action again. If using a rubber band, secure it around the container to mark the level of the starter before revival. This will help you assess the starter's growth during the revival process. Your starter should at least double in volume within 4 hours at room temperature if it is ready to be used in baking. 
4. Once your starter behaves as normal, maintain a regular sourdough feeding schedule and make some delicious bread! 

What To Do With All That Sourdough Discard?

Reviving frozen sourdough starter means you will have to feed it a little more often (or for longer periods of time) unit it is, once again, fit for purpose. And that, in turn, means plenty of sourdough discard to use up. Don't discard the discard! Here are some of our favourite Sourdough Discard recipes to try:

Extra Tips For Best Results

For the quickest revival of your beloved sourdough starter, follow these tips:

• Use fresh water and fresh flour to feed your defrosted sourdough starter for more nourishment. 
• Use luke warm water to speed up the process, especially if your room temperature is a little bit lower than 24-27°C. 
• If, after 2-3 feeds, you still have a sluggish starter, don't give up. Make sure to keep your starter in a warm spot, and carry on with daily feeding for a couple more days. 
• Watch your starter for any signs of spoilage, like mould growth, unpleasant musty aroma or discolouration. A spoilt starter should be discarded.  

How Many Feeds Will It Take To Revive My Frozen Starter?

It depends on:

• How long your starter has been frozen for. 
• The initial health and maturity of your starter.
• The temperature of the environment you are reviving your starter at.  

We find that it typically takes 2-3 feeds to have a healthy active starter after freezing it. However, you should always observe and test your starter before using it in baking. The general rule is: if it at least doubles in volume at room temperature within 4 hours, it's good to go! A small piece of good sourdough starter will also float in water, and have a tangy aroma. 

Can I Refreeze A Previously Frozen Starter?

You should not refreeze the starter that has recently been defrosted (ideally not for a couple of weeks). However, after fully reviving your starter and regular feedings, it can be safely refrozen again. As a general rule, I would recommend feeding your starter at least 10-12 times before re-freezing it. 

Other Sourdough Tips & Tricks

Want to learn more about maintaining your sourdough starter, baking with sourdough and storing it to preserve its texture and flavour? You may be interested in the articles below:

Popular Sourdough Bread Recipes To Try