Step 1

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).

Step 2

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.

Step 3

Once you've portioned out the sourdough starter, place it into the freezer to freeze for around 12 hours.

Step 4

Once the starter has frozen, remove the portions from the silicone molds and place them into a ziploc bag that is clearly labelled.

Step 5

Leave the sourdough starter portions in the freezer for up to 12 months (see notes).

Step 6

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.

Step 7

Allow the frozen sourdough starter to defrost at room temperature for around 4 hours or until it's liquid again.

Step 8

Add 50g of warm water and 50g of flour to the jar and stir vigorously. Allow it to double over the next 12 hours.

Step 9

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.