A little-discussed aspect of starters is the degree to which they can be — indeed probably should be — customized according to the type of bread you’re planning to bake. For example, my go-to outdoor oven bread is a pugliese. It’s got a lot of semolina flour in it, which means that in order to get the rise I want from the dough, I need to add a high-gluten (high-protein) flour to the mix.
So far so good. However one key factor is the starter. The starter makes up about 1/3 of the total volume of the dough. My recipe calls for a standard white flour starter. However if I use a white flour starter that I’ve built up (“fed”) using regular all-purpose flour (not a stronger, high gluten flour) then in the end I’ll get a lower-volume loaf, because a significant portion of my flour — the flour that’s in the starter — will be of the lower-gluten all-purpose variety.
The solution to the problem? Feed my starter with high-gluten flour. Sure, I could keep an entirely separate high-gluten “mother” if I wanted to. Some bakeries do that. For me that’s too much extra trouble. So what I’ll do is take a small quantity of my mother starter out of the container a day or two ahead of time, maybe an ounce or two, then begin feeding that offshoot starter on high gluten flour…increasing and increasing it until I have the amount of starter I need for the recipe. In this way I create my own custom, high-G starter. Easy easy.
I can use this same system if I want to grow a whole wheat starter, for example. Sure, the parent is still my usual white flour mother, but really I’m only using that mother to initiate the culture. By the time I’ve built up two ounces of white flour mother into 16 ounces of whole wheat starter, then combined that with more wheat flour to make a bread dough, no one will ever be able to tell that the kick-off point was my all-white-flour mother.
It’s true that some bakeries keep many different mothers in their refrigerators. The bakery where I got started kept four of them: white, high-gluten, whole wheat, and rye. But then we were under a lot of time pressure there. Bread doughs had to be mixed each evening and on-the-rise within a matter of a few hours so we could begin baking by midnight. We couldn’t afford to wait around to grow our own rye starter from a white flour mother. But we home bakers have that luxury. We can keep just one mother, and, as long as we keep it well fed and vibrant, can grow any kind of starter we want from it whenever we want. It’s a lot simpler than trying to juggle multiple starters in multiple flavors, and a lot less wasteful.
So let’s say you’re making whole wheat bread and the recipe calls for a pound of whole wheat starter. Whole wheat starters — like most whole wheat bread doughs — are a mix of white flour and whole wheat flour, anywhere from 1/3 white flour to 1/2 white flour in my experience. I’ll begin with two ounces of active white starter from my white flour mother (replacing the weight of what I took, of course, with white flour and water). I’ll then make a flour mix at whatever proportion the recipe author’s starter recipe calls for, maybe 1/3 white flour and 2/3 wheat flour, and begin feeding it. If the mother starter I began with is active, I can double my new starter’s size every four hours, first adding an ounce of my flour mix plus water, then two ounces of flour mix and water, and so on. I can do the same if I want a rye starter, a wheat-and-rye starter, whatever. Note that the amount of water will change depending on the the type of flour you’re using (wheat and rye flours are more absorbent), just look to your recipe to give you an idea for how wet (hydrated) the starter, and in the end the final dough, needs to be.
One thing to know about non-white-flour starters is that they look and behave differently than standard white flour starters. Especially where all-whole-wheat and all-rye starters are concerned, they may hardly rise and bubble at all. The reason of course is that whole wheat and coarse rye flours are loaded with bran and germ, both of which undermine rise. But as long as you’re seeing at least the odd pock mark here or there and the thing smells good, you’re doing fine. This is another advantage of using a well-maintained mother to create your exotic starters: you have the comfort of knowing that the culture you’re beginning with is robust and familiar, and that eliminates a lot of uncertainty about who/what is growing in the bowl.
So I hope this helps your understanding of starters and how flexible they really are. There’s a whole world to explore here if you decide to really get into it. Along the way you’ll discover that bread baking is a more flexible and forgiving — not to mention interesting — science than you may have at first thought.