Once your gluten-free sourdough starter is up and running, is actively bubbling after each feeding, and has been maturing for at least 10 to 14 days, it’s ready for baking. The starter is made up of living yeasts that need to be matured in order to make bread well. Hooray!
You will need around 3 3/4 cups/885 ml (about 850 g) of starter for the Sourdough Boule recipe linked below. Therefore, you will need to build up the starter before baking with it.
An easy way to do this is to create a leaven (or levain). “Leaven” is technically another word for starter, but in the baking world it is a term often used for a part of the starter that you build up separately to bake with. It allows you to create a bigger starter for baking without having to maintain a bigger starter for the long run.
MAKING YOUR LEAVEN FOR BAKING (FROM EITHER STARTER)
1. At this point with either starter creation method, you will have about 1 1/2 cups/355 ml (300 g) of mature starter. For the next feeding, stir well and pour all of the starter into the bigger container. I use a 2 quart/1.9 l Cambro plastic bucket. (clean and keep your smaller container to use again)
2. Add 1 1/2 cups/355ml (240 g) whole grain flour (brown rice, teff, or sweet white sorghum).
3. Add 1 1/2 cups/355ml (360 g) water.
4. Stir well and make sure there are no pockets of dry flour. Cover with lid. You will now have roughly 4 1/2 cups/1065 ml (900 g) of starter.
5. Let the leaven ferment for 3 to 8 hours or so–depending on the how active the yeast is. How long it takes your leaven to become ready is based on your kitchen and your starter.
6. Once the leaven is nice and bubbly and somewhat puffy on top–indicating active and happy yeast–it is ready to use in your bread dough. Stir well and pour off around 1/2 cup/118 ml (100g) of the leaven back into your smaller starter jar to maintain as your starter.
7. Use the remaining leaven–which will be roughly 4 cups/946 ml (800 g)–for your Sourdough Boule.