Feed a starter a few hours before freezing to ensure you have an active sourdough starter before beginning the freezing process.

Line a muffin tin with muffin liners (alternatively, you can use a silicone ice cube tray, or even just parchment paper set over a plate)

Using a clean non-metallic spoon, add about 1/4 cup of sourdough starter to each muffin liner or silicone mold (if using a piece of parchment paper on a plate, just place dollops of starter directly onto the parchment paper). I like to make 2 frozen portions for each type of sourdough starter at a time.

Place muffin tin, mold, or plate with sourdough into the freezer, uncovered for a few hours or over night (until fully frozen).

Once the sourdough starter portions are fully frozen, transfer to an airtight container. I like to fold the muffin liner around the frozen sourdough portions and place them in a freezer bag. You could also use a glass jar or container with a secure lid.

Make sure to label your container with the date of freezing and what kind of starter it is!

Remove one portion of sourdough starter from the freezer.

Peel away any muffin liner or parchment paper and place sourdough starter portion in the bottom of a medium sized bowl.

Cover the bowl and place in a somewhat warm place (around room temperature) for 6 to 8 hours, or overnight.

Once the portion is fully thawed and is liquid, add 1/4 cup of filtered water and 1/2 cup of flour and combine well with a non-metallic spoon.

Let the starter rest for about 8 hours or until is is bubbly and active.

Discard half of the sourdough mixture (you can use it in a sourdough discard recipe).

Feed the remaining starter with 1/4 cup of filtered water and 1/2 cup of flour.

If the new starter shows signs of activity (like little bubbles) at about 6 hours,  it can now be used for baking. If not, continue with regular feedings until it is bubbly and within 6 hours of feeding time.