We are talking about converting your starter, wither by feeding it with a different kind of flour or by increasing/ decreasing its hydration level. E.g. you have a starter you usually feed with white bread flour and you want to convert that starter to a rye one or you keep your starter at a 100% hydration and you would like to take that down to 70%.
If you want to feed your starter with a different flour
You can simply do it and there is no need to initiate a different starter (unless you want to, of course). You will use the starter you have to inoculate the new culture and by gradually phasing out the flour you are using now, you will end up with a different kind of starter.
How do you do it? Here’s an example.
If you want to build a rye starter and you have a white bread flour starter.
- Day 1, morning – feed 10 grams of your starter with 30 grams water, 20 grams white bread flour and 10 grams rye flour.
- Day 1, evening – feed 10 grams of starter with 30 grams water, 20 grams rye flour and 10 grams white bread flour.
- Day 2, morning – feed 10 grams of starter with 40 grams of water and 30 grams of rye flour.
- Day 2, evening and beyond – continue the same, by feeding the 10 grams of starter with 30 grams of water and rye flour.
If you want to convert your starter to a gluten-free one
If you want to convert your starter to a gluten-free one, the procedure is much the same as the one mentioned above, only you will feed it with gluten free flours (rice, buckwheat, quinoa, whatever crosses your mind). You might also want to keep on feeding it gluten-free flours for at least 3 days (feeding it twice daily with 30 grams water and 30 grams rice/buckwheat/quinoa or another type of gluten-free flour), just to make sure that there is no residual gluten from the initial culture in your gluten-free starter. We definitely recommend converting a regular starter to a gluten-free one rather than initiating a gluten-free starter, as they can be extremely fussy and take a very long time to gain strength
If you want to convert your starter to a different hydration level
Say you have a 100% hydration starter and you want to convert it to 70% hydration, simply reduce the hydration in a few feedings
- First feed – keep 10 grams starter and feed it 30 grams flour and 21 grams water
- Continue the same way for the following feedings
For simplicity, we have designed the feeding ratios as to end up with the 70% hydration level in a few feedings. When you calculate hydration, you must account for the hydration in the initial starter culture, so the first time you feed you starter, as per the example above, you will actually have a 74% hydration and will gradually decrease as you continue with your feedings (as your starter will carry less water each time). Of course, you can also adjust the hydration to the T from the first feed in one go.
It’s very important that for all the experiments you make converting starters, always keep your mother starter safe and fed. The last thing you want is for an experiment to go badly and lose your starter and need to start from scratch all over again. The mother starter will be the culture you turn to whenever you need to make another starter or if a recipe requires preparing a certain type of levain.