Can You Freeze Sourdough Starter?
This post may contain affiliate links.
You can freeze sourdough starter in an airtight container for up to a year without permanently damaging the starter. You don't have to feed the sourdough starter while it's frozen, which is a popular reason for putting your sourdough starter in the deep freeze.
Freezing a sourdough starter is a way to store the sourdough culture for a long time, without constant feeding, however it is only suitable for storing a mature starter if you aren't going to use it for longer periods.
You can successfully bake a loaf of sourdough bread from a sourdough starter that has been frozen, as long as you take the time to reactivate it after it's defrosted.
Quick Notes for Freezing a Sourdough Starter
- sourdough starter can be frozen for up to 12 months
- use an active starter that has been recently fed for best results
- freezing doesn't damage it but it will need to be fed before it's used after thawing
- you can only freeze a mature sourdough starter
- use heavy-duty freezer bags to avoid freezer burns and ice crystals forming
Why Freeze Sourdough Starter?
Freezing a sourdough starter can be a good solution for longer term storage if you aren't going to be baking for a while. Some of the reasons you might want to freeze your sourdough starter include:
- going on a long vacation
- needing a break from daily feeding and baking
- knowing you're going to be time poor for an extended period of time
- wanting to have an extra back up for your sourdough starter
While the wild yeast in a sourdough starter produce amazing bread, they do require more hands on work than baking with commercial yeast.
And sometimes, real life just gets in the way and you need a break from the constant feeding and maintenance.
Does Freezing Damage A Sourdough Starter?
Freezing a sourdough starter will not harm it, however, the lower temperatures will cause some of the yeast to die off. This is unavoidable but will not permanently damage your sourdough starter because as soon as you defrost it and feed it, the yeast colony will begin to reestablish themselves.
Yeast is one of the most resilient life-forms on our plant ... which is good news if your want to put your sourdough starter ice!
While yeast do not thrive in cold temperatures and in fact they hibernate when frozen, lactic acid bacteria and yeast can both survive a deep freeze.
Sourdough starters thrive in warm temperatures between 24C and 28C.
If you are worried about freezer burn, you can double bag your frozen sourdough starter, or wrap the plastic ziploc bag in aluminum foil to prevent it.
Snap freezing the pucks separately before adding them to the bag also prevents ice crystals from forming.
Can I Freeze A New Sourdough Starter?
You should only freeze a sourdough starter once it's mature. If your starter is less than 3 to 4 months and still in the establishment phase, it's not suitable for freezing and needs to continue on a feeding schedule of twice daily.
A mature sourdough starter will show many signs of readiness.
How To Freeze Sourdough Starter (simple steps)
- Creating a frozen starter is pretty simple, but it's a good idea to take your time and do it right, particularly if this is going to be a back up to your liquid sourdough starter.
- Make sure that your sourdough starter has been fed in the past few hours and is active and bubbly (like it would be if you were going to bake a loaf of sourdough bread).
- Divide the sourdough starter into 6 equal portions. You could use a silicone ice cube tray or cupcake liners. Remember that you want to be able to remove the frozen sourdough starter easily, so don't put it in anything that it could stick to easily. You don't need a piping bag or anything special, just use a spoon to place the sourdough starter into your chosen containers.
- Once you've portioned out the sourdough starter, place it into the freezer to freeze for around 4 to 6 hours (the time it takes will really depend on your freezer and the temperature it sits at but you really want to make sure that the top of the cubes are solid before removing them).
- Once the starter has frozen, remove the portions from the silicone molds and place them into a ziploc plastic bag that is clearly labelled.
- Leave the sourdough starter portions in the freezer for up to 12 months (see notes).
How To Defrost and Reactivate Sourdough Starter
- When you want to reactivate a portion of starter, take out a frozen portion (it should be around 50g). Place the frozen portion into a clean jar.
- Allow the frozen sourdough starter to defrost at room temperature for around 12 hours or until it's liquid again.
- Add 50g of lukewarm water and 50g of flour to the jar and give it a good stir. Allow it to double over the next 12 hours.
- Discard all but 50g of the sourdough starter. Feed the remaining 50g of starter in the jar with 50g of lukewarm water and 50g of flour.
- Repeat this step until the starter is doubling and active (like it was before you froze it). It should be ready to use in 2 to 3 feeds.
Once your sourdough starter thaws and is reactivated, it should behave like it did before you froze it and be an active sourdough starter . You can then use it to make sourdough bread, pizza dough and anything else you like.
I don't recommend refreezing your sourdough starter unless it's been fed and is active again first.
How Long Can A Sourdough Starter Be Frozen For?
The sourdough starter can be frozen safely for up to 12 months. It's more than likely that the sourdough starter can survive longer than this in the freezer, however, the longer you leave it in the freezer, the more yeast will die off, making it much harder to get it going when you want to.
I recommend refreshing your stash of frozen starter every 12 months to ensure the viability of your sourdough starter when you want to use it.
Ensuring you clearly label your frozen starter with the date will ensure that you don't forget when you put it in there.
Are There Alternatives To Freezing Sourdough Starter?
If you don't want to freeze your sourdough starter, but still want a backup starter or long term storage for your starter, you can dry it out. It's really easy to do and means that your sourdough starter can be kept safe at room temperature indefinitely. There is less chance of something happening to a dried sourdough starter.
You basically need to spread your sourdough starter onto a piece of parchment paper using an offset spatula or pastry brush and allow it to dry out completely. This can be done in lots of different ways, including in the oven or in a dehydrator.
You'll find a full guide to dehydrating your sourdough starter (and reactivating it) here.
What's The Difference Between Freezing a Sourdough Starter and Keeping It In The Fridge?
Refrigerating your sourdough starter keeps it at a higher temperature than freezing it, so it's a better option for short periods. A sourdough starter will survive in the fridge, unfed for a good few weeks.
This is a good storage option if you are going away for just a few weeks or just want a short break from baking. It is pretty quick to revive a sourdough starter from the fridge (even if it's been months).
You can find a full guide to storing your sourdough starter in the fridge here.
Frequently Asked Questions
Yes you can freeze sourdough starter discard. Freezing sourdough discard can be a good idea if you have too much to store in the fridge and you want to keep it to use in future baking recipes. Freezing the discard in small silicone molds means you can defrost small amounts when you need it.
It's best to freeze your sourdough starter when it's mature (at least 3-4 months old) and has been fed in the last few hours so it's active and bubbly. It's best not to freeze a new sourdough starter as the yeast colonies will not be established enough to survive the freezing process.
Yes you can freeze dried sourdough starter in a heavy-duty freezer bag. Dried starter chips can be frozen indefinitely.
You can freeze sourdough starter in a glass jar, however you will need to allow room for expansion. It's best to use a small jar (around 200 mls is perfect) with no more than 50g of fed, bubbly sourdough starter. Glass can be fragile when frozen and prone to cracking and shattering so care needs to be taken.
How To Freeze Sourdough Starter (and reactivate it)
Equipment
- Silicone Ice Cube Tray for freezing
- Ziploc Bags for storing
- Sharpie for labelling
Ingredients
- 300 g Sourdough Starter (fed and bubbly)
Instructions
How To Freeze Sourdough Starter
- Make sure that your sourdough starter has been fed in the past few hours and is active and bubbly (like it would be if you were going to bake a loaf of sourdough bread).
- Divide the sourdough starter into 6 equal portions (I've done 50g each in these photos). You could use a silicone ice cube tray or cupcake liners. Remember that you want to be able to remove the frozen sourdough starter easily, so don't put it in anything that it could stick to easily.
- Once you've portioned out the sourdough starter, place it into the freezer to freeze for around 12 hours.
- Once the starter has frozen, remove the portions from the silicone molds and place them into a ziploc bag that is clearly labelled.
- Leave the sourdough starter portions in the freezer for up to 12 months (see notes).
How to Defrost Sourdough Starter (and reactivate it)
- When you want to reactivate a portion of starter, take out a frozen portion (it should be around 50g). Place the frozen portion into a clean jar.
- Allow the frozen sourdough starter to defrost at room temperature for around 4 hours or until it's liquid again.
- Add 50g of warm water and 50g of flour to the jar and stir vigorously. Allow it to double over the next 12 hours.
- Discard all but 50g of the sourdough starter. Feed the remaining 50g of starter in the jar with 50g of warm water and 50g of flour. Repeat this step until the starter is doubling and active (like it was before you froze it). It should be ready to use in 2 to 3 feeds.