Troubleshooting Your Gluten-Free Sourdough Starter

Temperature is very important, especially in the very beginning or when trying to revive your starter. Keep the starter in a warm environment (ideally, 75° to 85°F or 24° to 29°C). If your oven has a proofing setting, consider yourself lucky. If not, place your starter in the oven with a pot of boiling-hot water. If it's warm in your environment and the starter doesn't bubble, it could be that your flour is not fermenting well. Try switching your flour brand, this has happened with bakers who use bulk-bin flours (not all bulk-bin flours will do this). If you are trying to revive a mature starter that seems to be struggling, increase the feeding to a higher ratio. For the Brown Rice-Teff Sourdough Starter in this class for instance, instead of the 1:1:1.19 ratio, you can do 1:2:2.38.

A healthy starter will smell like a mixture of yogurt and wine. But sometimes, when you use earthier flours like teff and buckwheat, the smell could be more pungent and you might be wondering if you are doing something wrong. Don't worry: it’s very hard to kill a starter so unless it smells like rotten food or has mold on it, it should be okay.

If you see pink or green spots or any fuzzy things growing on your starter, that’s mold and you should throw the starter away. This can happen when there is soap residue in the bowl or mason jar, which kills healthy microbes and allows mold to take over. Rinse your equipment only with water in between feedings to avoid any soap residue.

It’s normal for your starter to become liquid. As the starter hydrates and ferments, it tends to loosen up. It also can become more or less liquid as seasons and temperatures change.

This liquid, called hooch, is the mixture of water, acids, and ethanol that wild yeast produces during fermentation. It’s completely normal and indicates that your starter is hungry. If you have kept your starter in the refrigerator for a while without feeding, an accumulation of hooch is a good indicator that you need to refresh it. A second reason for this liquid is that water is not getting absorbed. This usually happens when your flour is overhydrated or too coarse and not hydrating well. In this case, reduce the amount of water you are feeding your starter by 10% and see if it keeps happening.

When you begin making sourdough bread you might have a specific taste in mind that you are looking for. Since gluten-free flours have different flavor profiles than wheat flour, each one will impact the flavor of your bread. Adding a little bit of teff and buckwheat will add a slightly more sour flavor to your starter, but it's not the only thing that will impact it (colder temperatures result in slightly more sour starters).

It is normal for your starter to rise and fall because without gluten, there are no elastic strands to trap the gases formed during fermentation. Bubbles form, but they fall quickly due to lack of elasticity. Always watch your starter and see when it has reached peak fermentation. Peak fermentation will happen right before you see the starter deflate. The top will dome and crack, then begin to slowly deflate. With time, you will develop an intuition or sense for when that moment is by watching how the starter rises. This is when you want to either use it (if you are dealing with the sponge to make bread) or refrigerate it.

The float test, which is an indication that a starter is at its peak, only works if your starter has specific density. Since a gluten-free starter doesn't trap gases the same as a gluten one, the float test is not an accurate tool. A gluten-free starter is denser than the gluten one. Also note there is no "glue" holding the starter together, so it will dissolve in water.

One of the most frequent questions Aran receives from bread bakers is whether they can convert an existing gluten-containing starter into a gluten-free one. The answer is yes, and it’s quite simple. Treat the gluten starter as you would the gluten-free one and start feeding it gluten-free flour and water. How long it will take for the starter to be 100% free of gluten particles is difficult to say. I would do multiple feedings (discarding in between just as you do for Brown Rice-Teff Sourdough Starter, and if you want to be completely sure it is gluten-free, test it with gluten-detecting test strips.)

You can take your established gluten-free starter and begin feeding it a different flour to create a completely new starter. Watch how the starter behaves. If you're converting a brown rice starter into a buckwheat one, for example, the first one might be very active but consecutive ones not as much, and that is because buckwheat flour doesn't ferment as quickly or get as bubbly as brown rice flour. Above all, remember, always keep enough of your healthy mother starter to get going. Don't use up all of it on experiments and deplete your source. A healthy starter is gold!